1993 FORD MONDEO spark plugs

The cylinder head is provided with two oil
galleries, one on the inlet side and one on the
exhaust, to ensure constant oil supply to the
camshaft bearings and hydraulic tappets. A
retaining valve (inserted into the cylinder
head’s top surface, in the middle, on the inlet
side) prevents these galleries from being
drained when the engine is switched off. The
valve incorporates a ventilation hole in its
upper end, to allow air bubbles to escape
from the system when the engine is restarted.
While the crankshaft and camshaft
bearings and the hydraulic tappets receive a
pressurised supply, the camshaft lobes and
valves are lubricated by splash, as are all
other engine components.
Valve clearances - general
It is necessary for a clearance to exist
between the tip of each valve stem and the
valve operating mechanism, to allow for the
expansion of the various components as the
engine reaches normal operating
temperature.
On most older engine designs, this meant
that the valve clearances (also known as
“tappet” clearances) had to be checked and
adjusted regularly. If the clearances were
allowed to be too slack, the engine would be
very noisy, its power output would suffer, and
its fuel consumption would increase. If the
clearances were allowed to be too tight, the
engine’s power output would be reduced,
and the valves and their seats could be
severely damaged.
The engines covered in this manual,
however, employ hydraulic tappets which use
the lubricating system’s oil pressure
automatically to take up the clearance
between each camshaft lobe and its
respective valve stem. Therefore, there is no
need for regular checking and adjustment of
the valve clearances, but it is essential that
onlygood-quality oil of the recommended
viscosity and specification is used in the
engine, and that this oil is always changed at
the recommended intervals. If this advice is
not followed, the oilways and tappets may
become clogged with particles of dirt, or
deposits of burnt (inferior) engine oil, so that
the system cannot work properly; ultimately,
one or more of the tappets may fail, and
expensive repairs may be required.
On starting the engine from cold, there will
be a slight delay while full oil pressure builds
up in all parts of the engine, especially in the
tappets; the valve components, therefore,
may well “rattle” for about 10 seconds or so,
and then quieten. This is a normal state of
affairs, and is nothing to worry about,
provided that all tappets quieten quickly and
stay quiet.
After the vehicle has been standing for
several days, the valve components may
“rattle” for longer than usual, as nearly all the
oil will have drained away from the engine’s
top end components and bearing surfaces.
While this is only to be expected, care mustbe taken not to damage the engine under
these circumstances - avoid high speed
running until all the tappets are refilled with oil
and operating normally. With the vehicle
stationary, hold the engine at no more than a
fast idle speed (maximum 2000 to 2500 rpm)
for 10 to 15 seconds, or until the noise
ceases. Do not run the engine at more than
3000 rpm until the tappets are fully recharged
with oil and the noise has ceased.
If the valve components are thought to be
noisy, or if a light rattle persists from the top
end after the engine has warmed up to
normal operating temperature, take the
vehicle to a Ford dealer for expert advice.
Depending on the mileage covered and the
usage to which each vehicle has been put,
some vehicles may be noisier than others;
only a good mechanic experienced in these
engines can tell if the noise level is typical for
the vehicle’s mileage, or if a genuine fault
exists. If any tappet’s operation is faulty, it
must be renewed (Section 13).
The following major repair operations can
be accomplished without removing the
engine from the vehicle. However, owners
should note that any operation involving the
removal of the sump requires careful
forethought, depending on the level of skill
and the tools and facilities available; refer to
the relevant text for details.
(a) Compression pressure - testing.
(b) Cylinder head cover - removal and
refitting.
(c) Timing belt covers - removal and refitting.
(d) Timing belt - renewal.
(e) Timing belt tensioner and toothed pulleys
- removal and refitting.
(f) Camshaft oil seals - renewal.
(g) Camshafts and hydraulic tappets -
removal and refitting.
(h) Cylinder head - removal, overhaul and
refitting.
(i) Cylinder head and pistons -
decarbonising.
(j) Sump - removal and refitting.
(k) Crankshaft oil seals - renewal.
(l) Oil pump - removal and refitting.
(m) Piston/connecting rod assemblies -
removal and refitting (but see note below).
(n) Flywheel/driveplate - removal and
refitting.
(o) Engine/transmission mountings - removal
and refitting.
Clean the engine compartment and the
exterior of the engine with some type of
degreaser before any work is done. It will
make the job easier, and will help to keep dirt
out of the internal areas of the engine.
Depending on the components involved, it
may be helpful to remove the bonnet, to
improve access to the engine as repairs are
performed (refer to Chapter 11 if necessary).Cover the wings to prevent damage to the
paint; special covers are available, but an old
bedspread or blanket will also work.
If vacuum, exhaust, oil or coolant leaks
develop, indicating a need for component/
gasket or seal replacement, the repairs can
generally be made with the engine in the
vehicle. The intake and exhaust manifold
gaskets, sump gasket, crankshaft oil seals
and cylinder head gasket are all accessible
with the engine in place.
Exterior components such as the intake
and exhaust manifolds, the sump, the oil
pump, the water pump, the starter motor, the
alternator and the fuel system components
can be removed for repair with the engine in
place.
Since the cylinder head can be removed
without lifting out the engine, camshaft and
valve component servicing can also be
accomplished with the engine in the vehicle,
as can renewal of the timing belt and toothed
pulleys.
In extreme cases caused by a lack of
necessary equipment, repair or renewal of
piston rings, pistons, connecting rods and
big-end bearings is possible with the engine
in the vehicle. However, this practice is not
recommended, because of the cleaning and
preparation work that must be done to the
components involved, and because of the
amount of preliminary dismantling work
required - these operations are therefore
covered in Part B of this Chapter.
1When engine performance is down, or if
misfiring occurs which cannot be attributed to
the ignition or fuel systems, a compression
test can provide diagnostic clues as to the
engine’s condition. If the test is performed
regularly, it can give warning of trouble before
any other symptoms become apparent.
2The engine must be fully warmed-up to
normal operating temperature, the oil level
must be correct, the battery must be fully
charged, and the spark plugs must be
removed. The aid of an assistant will be
required also.
3Disable the ignition system by unplugging
the ignition coil’s electrical connector, and
remove fuse 14 to disconnect the fuel pump.
4Fit a compression tester to the No 1
cylinder spark plug hole - the type of tester
which screws into the plug thread is to be
preferred.
5Have the assistant hold the throttle wide
open and crank the engine on the starter
motor; after one or two revolutions, the
compression pressure should build up to a
maximum figure, and then stabilise. Record
the highest reading obtained.
6Repeat the test on the remaining cylinders,
recording the pressure developed in each.
7At the time of writing, no compression
3 Compression test -
description and interpretation
2 Repair operations possible with
the engine in the vehicle
In-car engine repair procedures 2A•5
2A
procarmanuals.com

specifications were available from Ford, but a
typical reading would be in excess of 12 bars.
All cylinders should produce very similar
pressures; any difference greater than 10%
indicates the existence of a fault. Note that the
compression should build up quickly in a
healthy engine; low compression on the first
stroke, followed by gradually-increasing
pressure on successive strokes, indicates worn
piston rings. A low compression reading on the
first stroke, which does not build up during
successive strokes, indicates leaking valves or a
blown head gasket (a cracked head could also
be the cause). Deposits on the undersides of the
valve heads can also cause low compression.
8If the pressure in any cylinder is
considerably lower than the others, introduce
a teaspoonful of clean oil into that cylinder
through its spark plug hole, and repeat the
test.
9If the addition of oil temporarily improves
the compression pressure, this indicates that
bore or piston wear is responsible for the
pressure loss. No improvement suggests that
leaking or burnt valves, or a blown head
gasket, may be to blame.
10A low reading from two adjacent cylinders
is almost certainly due to the head gasket
having blown between them; the presence of
coolant in the engine oil will confirm this.
11If one cylinder is about 20 percent lower
than the others and the engine has a slightly
rough idle, a worn camshaft lobe or faulty
hydraulic tappet could be the cause.
12If the compression is unusually high, the
combustion chambers are probably coated
with carbon deposits. If this is the case, the
cylinder head should be removed and
decarbonised.
13On completion of the test, refit the spark
plugs, then reconnect the ignition system and
fuel pump.
General
1Top Dead Centre (TDC) is the highest point
in its travel up-and-down its cylinder bore
that each piston reaches as the crankshaftrotates. While each piston reaches TDC both
at the top of the compression stroke and
again at the top of the exhaust stroke, for the
purpose of timing the engine, TDC refers to
the piston position (usually No 1 piston) at the
top of its compression stroke.
2It is useful for several servicing procedures
to be able to position the engine at TDC.
3No 1 piston and cylinder are at the right-
hand (timing belt) end of the engine (right-
and left-hand are always quoted as seen from
the driver’s seat). Note that the crankshaft
rotates clockwise when viewed from the
right-hand side of the vehicle.
Locating TDC
4Remove all the spark plugs (Chapter 1).
5Disconnect both battery leads - see
Chapter 5, Section 1 - unless the starter
motor is to be used to turn the engine.
6Apply the handbrake and ensure that the
transmission is in neutral, then jack up the
front right-hand side of the vehicle and
support on an axle stand. Remove the
roadwheel.
7Remove the auxiliary drivebelt cover (see
Chapter 1) to expose the crankshaft pulley
and timing marks.
8It is best to rotate the crankshaft using a
spanner applied to the crankshaft pulley bolt;
however, it is possible also to use the starter
motor (switched on either by an assistant
using the ignition key, or by using a remote
starter switch) to bring the engine close to
TDC, then finish with a spanner. If the starter
is used, be sure to disconnect the battery
leads immediately it is no longer required.
9Note the two pairs of notches in the inner
and outer rims of the crankshaft pulley. In the
normal direction of crankshaft rotation
(clockwise, seen from the right-hand side of the
vehicle) the first pair of notches are irrelevant to
the vehicles covered in this manual, while the
second pair indicate TDC when aligned with
the rear edge of the raised mark on the sump.
Rotate the crankshaft clockwise until the
second pair of notches align with the edge of
the sump mark; use a straight edge extended
out from the sump if greater accuracy is
required (see illustrations).10Nos 1 and 4 cylinders are now at TDC,
one of them on the compression stroke.
Remove the oil filler cap; if No 4 cylinder
exhaust cam lobe is pointing to the rear of the
vehicle and slightly downwards, it is No 1
cylinder that is correctly positioned. If the
lobe is pointing horizontally forwards, rotate
the crankshaft one full turn (360°) clockwise
until the pulley notches align again, and the
lobe is pointing to the rear and slightly down.
No 1 cylinder will then be at TDC on the
compression stroke.
11Once No 1 cylinder has been positioned
at TDC on the compression stroke, TDC for
any of the other cylinders can then be located
by rotating the crankshaft clockwise 180° at a
time and following the firing order (see
Specifications).
12An alternative method of locating TDC is
to remove the cylinder head cover (see
Section 5) and to rotate the crankshaft
(clockwise, as described in paragraph 8
above) until the inlet valves for the cylinder
concerned have opened and just closed
again. Insert a length of wooden dowel
(approximately 150 mm/6 in long) or similar
into the spark plug hole until it rests on the
piston crown, and slowly further rotate the
crankshaft (taking care not to allow the dowel
to be trapped in the cylinder) until the dowel
stops rising - the piston is now at the top of
its compression stroke, and the dowel can be
removed.
13There is a “dead” area around TDC (as
the piston stops rising, pauses and then
begins to descend) which makes difficult the
exact location of TDC by this method; if
accuracy is required, either establish carefully
the exact mid-point of the dead area, or refer
to the timing marks (paragraph 9 above).
1Unplug the two electrical connectors and
disconnect the vacuum hose (where fitted),
then remove the air cleaner assembly cover
with the air mass meter, the resonator and the
plenum chamber (see Chapter 4).
2Disconnect the accelerator cable from the
5 Cylinder head cover-
removal and refitting
4 Top Dead Centre (TDC) for
No 1 piston - locating
2A•6 In-car engine repair procedures
4.9A Do not use crankshaft pulley’s first
pair of notches “A” - align second pair of
notches “B” with raised rib on sump “C” . . .4.9B . . . using a straight edge extended
out from the sump (arrowed) if greater
accuracy is required5.4 Disconnecting crankcase breather
hose from cylinder head cover union
procarmanuals.com

throttle linkage as described in Chapter 4.
Where fitted, disconnect also the cruise
control actuator cable (see Chapter 12).
3Remove the timing belt upper cover (see
Section 9).
4Disconnect the crankcase breather hose
from the cylinder head cover union (see
illustration).
5Unplug the HT leads from the spark plugs
and withdraw them, unclipping the leads from
the cover.
6Working progressively, unscrew the
cylinder head cover retaining bolts, noting the
spacer sleeve and rubber seal at each, then
withdraw the cover (see illustration).
7Discard the cover gasket; this mustbe
renewed whenever it is disturbed. Check that
the sealing faces are undamaged, and that
the rubber seal at each retaining bolt is
serviceable; renew any worn or damaged
seals.
8On refitting, clean the cover and cylinder
head gasket faces carefully, then fit a new
gasket to the cover, ensuring that it locates
correctly in the cover grooves (see
illustration).
9Refit the cover to the cylinder head, then
insert the rubber seal and spacer sleeve at
each bolt location (see illustration). Start all
bolts finger-tight, ensuring that the gasket
remains seated in its groove.
10Working in a diagonal sequence from the
centre outwards, and in two stages (see
Specifications), tighten the cover bolts to the
specified torque wrench setting.
11Refit the HT leads, clipping them into
place so that they are correctly routed; each
is numbered, and can also be identified by
the numbering on its respective coil terminal.
12Reconnect the crankcase breather hose,
and refit the timing belt upper cover.
Reconnect and adjust the accelerator cable,
then refit the air cleaner assembly cover with
the air mass meter, the resonator and the
plenum chamber (see Chapter 4).
Warning: Petrol is extremely
flammable, so take extra
precautions when disconnecting
any part of the fuel system. Don’t smoke,
or allow naked flames or bare light bulbs in
or near the work area. Don’t work in a
garage where a natural gas appliance
(such as a clothes dryer or water heater) is
installed. If you spill petrol on your skin,
rinse it off immediately. Have a fire
extinguisher rated for petrol fires handy,
and know how to use it.
Removal
1Park the vehicle on firm, level ground,
apply the handbrake firmly, and slacken the
nuts securing the right-hand front roadwheel.
2Relieve the fuel system pressure (see
Chapter 4).3Disconnect the battery negative (earth) lead
- see Chapter 5, Section 1.
4Unplugging the two electrical connectors
and disconnecting the vacuum hose (where
fitted), remove the air cleaner assembly cover
with the air mass meter, the resonator and the
plenum chamber (see Chapter 4).
5Disconnect the accelerator cable from the
throttle linkage as described in Chapter 4 -
where fitted, disconnect also the cruise
control actuator cable (see Chapter 12).
6Disconnect the crankcase breather hose
from the cylinder head cover union.
7Unbolt the upper part of the exhaust
manifold heat shield; unclip the coolant hose
to allow it to be withdrawn. Slacken the
sleeve nut securing the EGR pipe to the
manifold, remove the two screws securing
the pipe to the ignition coil bracket, then
unscrew the sleeve nut securing the pipe to
the EGR valve - see Chapter 6 for full details if
required.
8Remove the two screws securing the wiring
“rail” to the top of the manifold - this is simply
so that it can be moved as required to reach
the manifold bolts. Unplug their electrical
connectors to disconnect the camshaft
position sensor and the coolant temperature
sensor, then unclip the wiring from the ignition
coil bracket, and secure it to the manifold.
9Remove the three screws securing the
wiring “rail” to the rear of the manifold.
Releasing its wire clip, unplug the large
electrical connector (next to the fuel pressure
regulator) to disconnect the wiring of themanifold components from the engine wiring
loom.
10Marking or labelling them as they are
unplugged, disconnect the vacuum hoses as
follows:
(a) One from the rear of the throttle housing
(only the one hose - there is no need to
disconnect the second hose running to
the fuel pressure regulator).
(b) One from the union on the manifold’s left-
hand end.
(c) The braking system vacuum servo unit
hose (see Chapter 9 for details).
(d) One from the Exhaust Gas Recirculation
(EGR) valve.
11Equalise the pressure in the fuel tank by
removing the filler cap, then undo the fuel
feed and return lines connecting the engine to
the chassis (see Chapter 4). Plug or cap all
open fittings.
12Unbolt the power steering high-pressure
pipe and the earth lead from the cylinder
head rear support plate/engine lifting eye,
then unscrew the bolt securing the support
plate/lifting eye to the alternator mounting
bracket.
13Unscrew the six nuts securing the
engine/transmission right-hand mounting
bracket, then withdraw the bracket.
14Remove the alternator (see Chapter 5).
15Unbolt the alternator mounting bracket
from the rear of the cylinder block and
withdraw it, together with the cylinder head
rear support plate/engine lifting eye (see
illustration).
6 Inlet manifold -
removal and refitting
In-car engine repair procedures 2A•7
2A
5.8 Ensure gasket is located correctly in
cover groove5.6 Removing cylinder head cover
5.9 Ensure rubber seal is fitted to each
cover bolt spacer, as shown6.15 Alternator mounting bracket must be
unbolted from rear of cylinder block to
permit access to inlet manifold nut
procarmanuals.com

1With the vehicle parked on firm level
ground, open the bonnet and disconnect the
battery negative (earth) lead - see Chapter 5,
Section 1 (see illustration).
2Unbolt the power steering high-pressure
pipe from the cylinder head rear support
plate/engine lifting eye, and from the front
support plate/pump bracket.
3Unscrew the six nuts securing the
engine/transmission right-hand mounting
bracket, then withdraw the bracket.
4Slacken the water pump pulley bolts.5Remove the cylinder head cover (see
Section 5).
6Remove the spark plugs, covering their
holes with clean rag, to prevent dirt or other
foreign bodies from dropping in (see Chap-
ter 1).
7Remove the auxiliary drivebelt (see Chap-
ter 1).
8Rotate the crankshaft clockwise until the
second pair of notches in the pulley rim align
with the edge of the sump mark, so that Nos
1 and 4 cylinders are at TDC (see Section 4).9Unbolt and remove the water pump pulley
and the auxiliary drivebelt idler pulley.
10Obtain Ford service tool 21-162, or
fabricate a substitute from a strip of metal
5 mm thick (while the strip’s thickness is
critical, its length and width are not, but
should be approximately 180 to 230 mm by
20 to 30 mm). Check that Nos 1 and 4
cylinders are at Top Dead Centre (TDC) - No 1
on the compression stroke - by resting this
tool on the cylinder head mating surface, and
sliding it into the slot in the left-hand end of
both camshafts (see illustration). The tool
should slip snugly into both slots while resting
on the cylinder head mating surface; if one
camshaft is only slightly out of alignment, it is
permissible to use an open-ended spanner to
rotate the camshaft gently and carefully until
the tool will fit.
11If both camshaft slots (they are machined
significantly off-centre) are below the level of
the cylinder head mating surface, rotate the
crankshaft through one full turn clockwise
and fit the tool again; it should now fit as
described in the previous paragraph.
12With the camshaft aligning tool remaining
in place, remove the crankshaft pulley. Do not
use the locked camshafts to prevent the
crankshaft from rotating - use only the locking
methods described in Section 8.
13Remove the timing belt lower and middle
covers (see Section 9).
14With the camshaft aligning tool still in
place, slacken the tensioner bolt, and use an
Allen key inserted into its centre to rotate the
tensioner clockwise as far as possible away
from the belt; retighten the bolt to secure the
tensioner clear of the timing belt (see
illustration).
15If the timing belt is to be re-used, use
white paint or similar to mark its direction of
rotation, and note from the manufacturer’s
markings which way round it is fitted.
Withdraw the belt (see illustration). Do not
rotate the crankshaft until the timing belt is
refitted.
16If the belt is being removed for reasons
other than routine renewal, check it carefully
for any signs of uneven wear, splitting, cracks
(especially at the roots of the belt teeth) or
In-car engine repair procedures 2A•11
2A
10.10 Fit camshaft aligning tool to ensure
engine is locked with Nos 1 and 4 cylinders
at TDC10.14 Slacken tensioner bolt, and use
Allen key to rotate tensioner away from
timing belt . . .10.15 . . . then withdraw timing belt
10.1 Timing belt and cover details
1 Timing belt upper cover
2 Inlet camshaft toothed pulley
3 Exhaust camshaft toothed pulley
4 Timing belt
5 Timing belt tensioner
6 Crankshaft toothed pulley
7 Timing belt middle cover
8 Timing belt lower cover
9 Crankshaft pulley
10 Water pump pulley
procarmanuals.com

gear linkage heat shield. Reconnect the
gearchange linkage and transmission support
rods to the transmission, adjusting the linkage
using the marks made on removal (see
Chapter 7, Part A, for details).
56Re-install the remaining components and
fasteners in the reverse order of removal.
57Add coolant, engine oil and transmission
fluids as needed (see Chapter 1).
58Run the engine, and check for proper
operation and the absence of leaks. Shut off
the engine, and recheck the fluid levels.
59Remember that, since the front suspension
subframe and steering gear have been
disturbed, the wheel alignment and steering
angles must be checked fully and carefully as
soon as possible, with any necessary
adjustments being made. This operation is best
carried out by an experienced mechanic, using
proper checking equipment; the vehicle should
therefore be taken to a Ford dealer or similarly-
qualified person for attention.
1It is much easier to dismantle and work on
the engine if it is mounted on a portable engine
stand. These stands can often be hired from a
tool hire shop. Before the engine is mounted
on a stand, the flywheel/driveplate should be
removed (Part A of this Chapter, Section 21)
so that the stand bolts can be tightened into
the end of the cylinder block/crankcase.
2If a stand is not available, it is possible to
dismantle the engine with it mounted on
blocks, on a sturdy workbench or on the floor.
Be extra-careful not to tip or drop the engine
when working without a stand.
3If you are going to obtain a reconditioned
engine, all external components must be
removed first, to be transferred to the
replacement engine (just as they will if you are
doing a complete engine overhaul yourself).
Note:When removing the external
components from the engine, pay close
attention to details that may be helpful or
important during refitting. Note the fitted
position of gaskets, seals, spacers, pins,
washers, bolts and other small items.These
external components include the following:
(a) Alternator and brackets (Chapter 5).
(b) HT leads and spark plugs (Chapter 1).
(c) Thermostat and housing (Chapter 3).
(d) Dipstick tube.
(e) Fuel injection system components
(Chapter 4).
(f) All electrical switches and sensors - refer
to the appropriate Chapter.
(g) Inlet and exhaust manifolds (Part A of this
Chapter).
(h) Oil filter (Chapter 1).
(i) Engine/transmission mounting brackets
(Part A of this Chapter, Section 22).
(j) Flywheel/driveplate (Part A of this
Chapter, Section 21).
4If you are obtaining a “short” engine (whichconsists of the engine cylinder
block/crankcase, crankshaft, pistons and
connecting rods all assembled), then the
cylinder head, sump, oil pump, and timing belt
will have to be removed also.
5If you are planning a complete overhaul, the
engine can be dismantled and the internal
components removed in the following order.
(a) Inlet and exhaust manifolds (Part A of this
Chapter).
(b) Timing belt, toothed pulleys and
tensioner, and timing belt inner cover
(Part A of this Chapter).
(c) Cylinder head (Part A of this Chapter,
Section 14).
(d) Flywheel/driveplate (Part A of this
Chapter, Section 21).
(e) Sump (Part A of this Chapter, Section 15).
(f) Oil pump (Part A of this Chapter, Sec-
tion 16).
(g) Piston/connecting rod assemblies
(Section 9).
(h) Crankshaft (Section 10).
6Before beginning the dismantling andoverhaul procedures, make sure that you have
all of the correct tools necessary. Refer to the
introductory pages at the beginning of this
manual for further information.
Note:New and reconditioned cylinder heads
are available from the manufacturers, and
from engine overhaul specialists. Due to the
fact that some specialist tools are required for
the dismantling and inspection procedures,
and new components may not be readily
available (refer to Section 1 of this Part), it may
be more practical and economical for the
home mechanic to purchase a reconditioned
head, rather than to dismantle, inspect and
recondition the original head.
1Remove the camshafts and hydraulic
tappets (Part A of this Chapter, Section 13),
being careful to store the hydraulic tappets as
described (see illustration).
6 Cylinder head - dismantling
5 Engine overhaul-
dismantling sequence
Engine removal and general engine overhaul procedures 2B•9
2B
6.1 Cylinder head components
1 Hydraulic tappet
2 Valve collets
3 Valve spring upper seat
4 Valve spring5 Valve spring lower
seat/stem oil seal
6 Oil-retaining valve
7 Engine lifting eye
8 Cylinder head gasket9 Inlet valve
10 Locating dowels
11 Exhaust valve
12 Cylinder head bolt
procarmanuals.com

rod’s big-end onto the crankpin. The piston
rings may try to pop out of the ring
compressor just before entering the cylinder
bore, so keep some pressure on the ring
compressor. Work slowly, and if any
resistance is felt as the piston enters the
cylinder, stop immediately. Find out what’s
binding, and fix it before proceeding. Do not,
for any reason, force the piston into the
cylinder - you might break a ring and/or the
piston.
10To check the big-end bearing running
clearance, cut a piece of the appropriate-size
Plastigage slightly shorter than the width of
the connecting rod bearing, and lay it in place
on the No 1 crankpin (big-end) journal, parallel
with the crankshaft centre-line (see illus-
tration 17.6).
11Clean the connecting rod-to-cap mating
surfaces, and refit the big-end bearing cap.
Make sure the etched number on the cap is
on the same side as that on the rod (see
illustration). Tighten the cap bolts evenly -
first use a torque wrench to tighten the bolts
to the specified (first stage) torque setting,
then use an ordinary socket extension bar
and an angle gauge to tighten the bolts
further through the specified (second stage)
angle. Use a thin-wall socket, to avoid
erroneous torque readings that can result if
the socket is wedged between the cap and
nut. If the socket tends to wedge itself
between the nut and the cap, lift up on it
slightly until it no longer contacts the cap.
Don’t rotate the crankshaft at any time during
this operation!
12Unscrew the bolts and detach the cap,
being very careful not to disturb the
Plastigage.
13Compare the width of the crushed
Plastigage to the scale printed on the
Plastigage envelope, to obtain the running
clearance (see illustration 17.10). Compare it
to the Specifications, to make sure the
clearance is correct.
14If the clearance is not as specified, seek
the advice of a Ford dealer or similar engine
reconditioning specialist - if the crankshaft
journals are in good condition (see Sec-
tion 13), it may be possible simply to renew
the shells to achieve the correct clearance. If
this is not possible, the crankshaft must bereground by a specialist, who can also supply
the necessary undersized shells. First though,
make sure that no dirt or oil was trapped
between the bearing shells and the
connecting rod or cap when the clearance
was measured. Also, recheck the crankpin
diameter. If the Plastigage was wider at one
end than the other, the crankpin journal may
be tapered (see Section 13).
15Carefully scrape all traces of the
Plastigage material off the journal and the
bearing surface. Be very careful not to scratch
the bearing - use your fingernail or the edge of
a credit card.
Final piston/connecting rod
refitting
16Make sure the bearing surfaces are
perfectly clean, then apply a uniform layer of
clean molybdenum disulphide-based grease,
engine assembly lubricant, or clean engine oil,
to both of them. You’ll have to push the piston
into the cylinder to expose the bearing surface
of the shell in the connecting rod.
17Slide the connecting rod back into place
on the crankpin (big-end) journal, refit the big-
end bearing cap, and then tighten the bolts in
two stages, as described above.
18Repeat the entire procedure for the
remaining piston/connecting rod assemblies.
19The important points to remember are:
(a) Keep the backs of the bearing shells and
the recesses of the connecting rods and
caps perfectly clean when assembling
them.
(b) Make sure you have the correct
piston/rod assembly for each cylinder -
use the etched cylinder numbers to
identify the front-facing side of both the
rod and its cap.
(c) The arrow on the piston crown must face
the timing belt end of the engine.
(d) Lubricate the cylinder bores with clean
engine oil.
(e) Lubricate the bearing surfaces when
refitting the big-end bearing caps after the
running clearance has been checked.
20After all the piston/connecting rod
assemblies have been properly installed,
rotate the crankshaft a number of times by
hand, to check for any obvious binding.1With the engine refitted in the vehicle,
double-check the engine oil and coolant
levels. Make a final check that everything has
been reconnected, and that there are no tools
or rags left in the engine compartment.
2With the spark plugs removed and the
ignition system disabled by unplugging the
ignition coil’s electrical connector, remove
fuse 14 to disconnect the fuel pump. Turn the
engine on the starter until the oil pressure
warning light goes out.
3Refit the spark plugs, and connect all the
spark plug (HT) leads (Chapter 1). Reconnect
the ignition coil wiring, refit the fuel pump fuse,
then switch on the ignition and listen for the fuel
pump; it will run for a little longer than usual,
due to the lack of pressure in the system.
4Start the engine, noting that this also may
take a little longer than usual, due to the fuel
system components being empty.
5While the engine is idling, check for fuel,
coolant and oil leaks. Don’t be alarmed if
there are some odd smells and smoke from
parts getting hot and burning off oil deposits.
If the hydraulic tappets have been disturbed,
some valve gear noise may be heard at first;
this should disappear as the oil circulates fully
around the engine, and normal pressure is
restored in the tappets.
6Keep the engine idling until hot water is felt
circulating through the top hose, check that it
idles reasonably smoothly and at the usual
speed, then switch it off.
7After a few minutes, recheck the oil and
coolant levels, and top-up as necessary
(Chapter 1).
8If they were tightened as described, there is
no need to re-tighten the cylinder head bolts
once the engine has first run after reassembly
- in fact, Ford state that the bolts must notbe
re-tightened.
9If new components such as pistons, rings
or crankshaft bearings have been fitted, the
engine must be run-in for the first 500 miles
(800 km). Do not operate the engine at full-
throttle, or allow it to labour in any gear during
this period. It is recommended that the oil and
filter be changed at the end of this period.
19 Engine -
initial start-up after overhaul
2B•22 Engine removal and general engine overhaul procedures
procarmanuals.com

5If you are renewing the battery, make sure
that you get one that’s identical, with the
same dimensions, amperage rating, cold
cranking rating, etc. Dispose of the old battery
in a responsible fashion. Most local authorities
have facilities for the collection and disposal
of such items - batteries contain sulphuric
acid and lead, and should not be simply
thrown out with the household rubbish!
6Refitting is the reverse of the removal
procedure.
Note:See also the relevant Sections of
Chapter 1.
1Periodically inspect the entire length of
each battery lead for damage, cracked or
burned insulation, and corrosion. Poor battery
lead connections can cause starting problems
and decreased engine performance.
2Check the lead-to-terminal connections at
the ends of the leads for cracks, loose wire
strands and corrosion. The presence of white,
fluffy deposits under the insulation at the lead
terminal connection is a sign that the lead is
corroded and should be renewed. Check the
terminals for distortion, missing clamp bolts,
and corrosion.
3When removing the leads, always
disconnect the negative lead first, and
reconnect it last (see Section 1). Even if only
the positive lead is being renewed, be sure to
disconnect the negative lead from the battery
first (see Chapter 1 for further information
regarding battery lead removal).
4Disconnect the old leads from the battery,
then trace each of them to their opposite
ends, and detach them from the starter
solenoid and earth terminals. Note the routing
of each lead, to ensure correct installation.
5If you are renewing either or both of the old
leads, take them with you when buying new
leads. It is vitally important that you replace
the leads with identical parts. Leads have
characteristics that make them easy to
identify: positive leads are usually red, larger
in cross-section, and have a larger-diameter
battery post clamp; earth leads are usually
black, smaller in cross-section and have a
slightly smaller-diameter clamp for the
negative post.
6Clean the threads of the solenoid or earth
connection with a wire brush to remove rust
and corrosion.
7Attach the lead to the solenoid or earth
connection, and tighten the mounting nut/bolt
securely.
8Before connecting a new lead to thebattery, make sure that it reaches the battery
post without having to be stretched.
9Connect the positive lead first, followed by
the negative lead.
General
The ignition system includes the ignition
switch, the battery, the crankshaft speed/
position sensor, the coil, the primary (low
tension/LT) and secondary (high tension/HT)
wiring circuits, and the spark plugs. On models
with automatic transmission, a separate
ignition module is also fitted, its functions
being incorporated in the ECU on models with
manual transmission. The ignition system is
controlled by the engine management
system’s Electronic Control Unit (ECU). Using
data provided by information sensors which
monitor various engine functions (such as
engine speed and piston position, intake air
mass and temperature, engine coolant
temperature, etc.), the ECU ensures a
perfectly-timed spark under all conditions (see
Chapter 6). Note:The ignition timing is under
the full control of the ECU, and cannot be
adjusted - see Section 8 for further details.
Precautions
When working on the ignition system, take
the following precautions:
(a) Do not keep the ignition switch on for more
than 10 seconds if the engine will not start.
(b) If a separate tachometer is ever required
for servicing work, consult a dealer
service department before buying a
tachometer for use with this vehicle -
some tachometers may be incompatible
with this ignition system - and always
connect it in accordance with the
equipment manufacturer’s instructions.
(c) Never connect the ignition coil terminals
to earth. This could result in damage to
the coil and/or the ECU or ignition module
(whichever is fitted).
(d) Do not disconnect the battery when the
engine is running.
(e) Make sure that the ignition module (where
fitted) is properly earthed.
(f) Refer to the warning at the beginning of
the next Section concerning HT voltage.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.Note: This is an initial check of the “ignition
part” of the main engine management system,
to be carried out as part of the preliminary
checks of the complete engine management
system (see Chapter 6).
1If the engine turns over but won’t start,
disconnect the (HT) lead from any spark plug,
and attach it to a calibrated tester (available at
most automotive accessory shops). Connect
the clip on the tester to a good earth - a bolt
or metal bracket on the engine. If you’re
unable to obtain a calibrated ignition tester,
have the check carried out by a Ford dealer
service department or similar. Any other form
of testing (such as jumping a spark from the
end of an HT lead to earth) is not
recommended, because of the risk of
personal injury, or of damage to the
ECU/ignition module (see notes above and in
Section 4).
2Crank the engine and watch the end of the
tester to see if bright blue, well-defined sparks
occur.
3If sparks occur, sufficient voltage is
reaching the plug to fire it. Repeat the check
at the remaining plugs, to ensure that all leads
are sound and that the coil is serviceable.
However, the plugs themselves may be fouled
or faulty, so remove and check them as
described in Chapter 1.
4If no sparks or intermittent sparks occur,
the spark plug lead(s) may be defective -
check them as described in Chapter 1.
5If there’s still no spark, check the coil’s
electrical connector, to make sure it’s clean
and tight. Check for full battery voltage to the
coil at the connector’s centre terminal. The
coil is earthed through the ECU - do not
attempt to check this. Check the coil itself
(see Section 6). Make any necessary repairs,
then repeat the check again.
6The remainder of the system checks should
be left to a dealer service department or other
qualified repair facility, as there is a chance
that the ECU may be damaged if tests are not
performed properly.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.
Check
1Having checked that full battery voltage is
available at the centre terminal of the coil’s
electrical connector (see Section 5),
disconnect the battery negative (earth) lead -
see Section 1.
2Unplug the coil’s electrical connector, if not
already disconnected.
6 Ignition coil -
removal and refitting
5 Ignition system - testing
4 Ignition system - general
information and precautions
3 Battery leads -
check and renewal
Engine electrical systems 5•3
5
Apply a light coat of battery
terminal corrosion inhibitor,
or petroleum jelly, to the
threads, to prevent future
corrosion.
procarmanuals.com

2The function of these components is to
reduce the emission of unburned
hydrocarbons from the crankcase, and to
minimise the formation of oil sludge. By
ensuring that a depression is created in the
crankcase under most operating conditions,
particularly at idle, and by positively inducing
fresh air into the system, the oil vapours and
“blow-by” gases collected in the crankcase
are drawn from the crankcase, through the oil
separator, into the inlet tract, to be burned by
the engine during normal combustion.
Checking
3Checking procedures for the system
components are included in Chapter 1.
Component renewal
Cylinder head-to-air cleaner hose
4See Chapter 1.
Positive Crankcase Ventilation (PCV)
valve
5The valve is plugged into the oil separator.
Depending on the tools available, access to
the valve may be possible once the pulse-air
assembly has been removed (see Section 7).
If this is not feasible, proceed as outlined in
paragraph 6 below.
Oil separator
6Remove the exhaust manifold (see Chap-
ter 2, Part A). The Positive Crankcase
Ventilation (PCV) valve can now be unplugged
and flushed, or renewed, as required, as
described in Chapter 1.
7Unbolt the oil separator from the cylinder
block/crankcase, and withdraw it; remove and
discard the gasket.
8Flush out or renew the oil separator, as
required (see Chapter 1).
9On reassembly, fit a new gasket, and
tighten the fasteners to the torque wrench
settings given in the Specifications Section of
Chapter 2, Part B.
10The remainder of the refitting procedure is
the reverse of removal. Refill the cooling
system (see Chapter 1). Run the engine,
check for exhaust leaks, and check the
coolant level when it is fully warmed-up.
General information
1The exhaust gases of any petrol engine
(however efficient or well-tuned) consist
largely (approximately 99 %) of nitrogen (N
2),
carbon dioxide (CO
2), oxygen (O2), other inert
gases and water vapour (H
2O). The remaining
1 % is made up of the noxious materials
which are currently seen (CO
2apart) as the
major polluters of the environment: carbon
monoxide (CO), unburned hydrocarbons (HC),oxides of nitrogen (NO
x) and some solid
matter, including a small lead content.
2Left to themselves, most of these pollutants
are thought eventually to break down naturally
(CO and NO
x, for example, break down in the
upper atmosphere to release CO
2) having first
caused ground-level environmental problems.
The massive increase world-wide in the use of
motor vehicles, and the current popular
concern for the environment has caused the
introduction in most countries of legislation, in
varying degrees of severity, to combat the
problem.
3The device most commonly used to clean
up vehicle exhausts is the catalytic converter.
It is fitted into the vehicle’s exhaust system,
and uses precious metals (platinum and
palladium or rhodium) as catalysts to speed
up the reaction between the pollutants and
the oxygen in the vehicle’s exhaust gases, CO
and HC being oxidised to form H
2O and CO2and (in the three-way type of catalytic
converter) NO
xbeing reduced to N2. Note:
The catalytic converter is not a filter in the
physical sense; its function is to promote a
chemical reaction, but it is not itself affected
by that reaction.
4The converter consists of an element (or
“substrate”) of ceramic honeycomb, coated
with a combination of precious metals in such
a way as to produce a vast surface area over
which the exhaust gases must flow; the whole
being mounted in a stainless-steel box. A
simple “oxidation” (or “two-way”) catalytic
converter can deal with CO and HC only,
while a “reduction” (or “three-way”) catalytic
converter can deal with CO, HC and NO
x.
Three-way catalytic converters are further
sub-divided into “open-loop” (or
“uncontrolled”) converters which can remove
50 to 70 % of pollutants and “closed-loop”
(also known as “controlled” or “regulated”)
converters which can remove over 90 % of
pollutants.
5The catalytic converter fitted to the Mondeo
models covered in this manual is of the three-
way closed-loop type.
6The catalytic converter is a reliable and
simple device, which needs no maintenance
in itself, but there are some facts of which an
owner should be aware if the converter is to
function properly for its full service life.
(a) DO NOT use leaded petrol in a vehicle
equipped with a catalytic converter - the
lead will coat the precious metals,
reducing their converting efficiency, and
will eventually destroy the converter; it will
also affect the operation of the oxygen
sensor, requiring its renewal if lead-
fouled. Opinions vary as to how much
leaded fuel is necessary to affect the
converter’s performance, and whether it
can recover even if only unleaded petrol is
used afterwards; the best course of action
is, therefore, to assume the worst, and to
ensure that NO leaded petrol is used at
any time.
(b) Always keep the ignition and fuel systemswell-maintained in accordance with the
manufacturer’s schedule (Chapter 1) -
particularly, ensure that the air filter
element, the fuel filter and the spark plugs
are renewed at the correct intervals. If the
intake air/fuel mixture is allowed to
become too rich due to neglect, the
unburned surplus will enter and burn in
the catalytic converter, overheating the
element and eventually destroying the
converter.
(c) If the engine develops a misfire, do not
drive the vehicle at all (or at least as little
as possible) until the fault is cured - the
misfire will allow unburned fuel to enter
the converter, which will result in its
overheating, as noted above. For the
same reason, do not persist if the engine
refuses to start - either trace the problem
and cure it yourself, or have the vehicle
checked immediately by a qualified
mechanic.
(d) Avoid allowing the vehicle to run out of
petrol.
(e) DO NOT push- or tow-start the vehicle
unless no other alternative exists,
especially if the engine and exhaust are at
normal operating temperature. Starting
the engine in this way may soak the
catalytic converter in unburned fuel,
causing it to overheat when the engine
does start - see (b) above.
(f) DO NOT switch off the ignition at high
engine speeds, in particular, do not “blip”
the throttle immediately before switching
off. If the ignition is switched off at
anything above idle speed, unburned fuel
will enter the (very hot) catalytic converter,
with the possible risk of its igniting on the
element and damaging the converter.
(g) Avoid repeated successive cold starts
followed by short journeys. If the
converter is never allowed to reach its
proper working temperature, it will gather
unburned fuel, allowing some to pass into
the atmosphere and the rest to soak in
the element, causing it to overheat when
a long journey is made - see (b) above.
(h) DO NOT use fuel or engine oil additives -
these may contain substances harmful to
the catalytic converter. Similarly, DO NOT
use silicone-based sealants on any part of
the engine or fuel system, and do not use
exhaust sealants on any part of the
exhaust system upstream of the catalytic
converter. Even if the sealant itself does
not contain additives harmful to the
converter, pieces of it may break off and
foul the element, causing local
overheating.
(i) DO NOT continue to use the vehicle if the
engine burns oil to the extent of leaving a
visible trail of blue smoke. Unburned
carbon deposits will clog the converter
passages and reduce its efficiency; in
severe cases, the element will overheat.
(j) Remember that the catalytic converter
operates at very high temperatures -
9 Catalytic converter -
general information, checking
and component renewal
Emissions control systems 6•19
6
procarmanuals.com