1993 FORD SIERRA oil pressure

Cooling system
Drivebelt tensions:
Air conditioning system compressor . . . . . . . . . . . . . . . . . . . . . . . . .10.0 mm (0.4 in) deflection at the midpoint of the belt’s longest run
under firm thumb pressure
Coolant pump/alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.0 mm (0.4 in) deflection midway between coolant pump and
alternator (or power steering pump) pulleys under firm thumb pressure
Fuel system
Air filter element:
Carburettor type:
1.3 and 1.6 litre (SOHC - Ford carburettor) . . . . . . . . . . . . . . . . . .Champion W110
1.6 litre (SOHC - Weber carburettor) and 1.8 litre SOHC . . . . . . . .Champion W118
1.6 litre (SOHC - 1984-on) and 2.0 litre SOHC . . . . . . . . . . . . . . . .Champion W152
1.8 litre CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion W219
2.0 litre DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion W152
Fuel injection type:
2.0 litre SOHC and DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion U507
1.6 and 1.8 litre (R6A type) CVH . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion W219
Fuel filter:
All fuel injection models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion L204
Ignition system
Spark plugs:
Make and type:
All except 1.8 CVH, CVH (R6A), 2.0 DOHC and P100 . . . . . . . . . . . .Champion RF7YCC or RF7YC
1.8 litre CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion RC7YCC or RC7YC
P100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion RF7YC or F7YC
1.6 and 1.8 litre (R6A type) CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion RC7YCC
2.0 litre DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion RC7YCC
Electrode gap*:
Champion F7YCC or RC7YCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.8 mm (0.032 in)
Champion RF7YC, F7YC or RC7YC . . . . . . . . . . . . . . . . . . . . . . . . . .0.7 mm (0.028 in)
Ignition HT leads
Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 k ohms maximum per lead
Type:
All SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion LS-09 or LS-10 boxed set
1.8 litre CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion LS-10 boxed set
1.6 and 1.8 litre (R6A type) CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion LS-30 boxed set
2.0 litre DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Champion LS-29 boxed set
*The spark plug gap quoted is that recommended by Champion for their specified plugs listed above. If spark plugs of any other type are to be
fitted, refer to their manufacturer’s recommendations.
Brakes
Brake pad friction material minimum thickness . . . . . . . . . . . . . . . . . . .1.5 mm (0.06 in)
Brake shoe friction material minimum thickness . . . . . . . . . . . . . . . . . .1.0 mm (0.04 in)
Torque wrench settingsNmlbf ft
Engine oil drain plug:
SOHC and DOHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2816 to 21
CVH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 3015 to 22
Engine block coolant drain plug (where fitted) . . . . . . . . . . . . . . . . . . . .21 to 25 16 to 18
Manual gearbox:
Oil filler/level plug:
A,B,C and N types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 to 4124 to 30
MT75 type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 to 4121 to 30
Oil drain plug:
MT75 type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 to 4121 to 30
Final drive oil filler plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 to 4526 to 33
Roadwheel nuts:
Saloon, Hatchback and Estate models (steel and alloy wheels) . . . .70 to 10052 to 74
P100 models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 to 9063 to 66
Spark plugs:
SOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2815 to 21
CVH models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 to 3313 to 24
DOHC models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 to 2111 to 15
Brake caliper guide bolts:
Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 to 3523 to 26
1•2Servicing specifications

1•4Maintenance schedule
Every 250 miles (400 km) or weekly
m mCheck the engine oil level (Section 3)
m mCheck the engine coolant level (Section 3)
m mCheck the brake fluid level (Section 3)
m mCheck the power steering fluid level (Section 3)
m mCheck the screen washer fluid level (Section 3)
m mVisually examine the tyres for tread depth, and wear
or damage (Section 4)
m mCheck and if necessary adjust the tyre pressures
(Section 4)
m mCheck and if necessary top-up the battery electrolyte
level - where applicable (Section 6)
m mCheck the operation of the horn, all lights, and the
wipers and washers (Sections 5 and 7)
Every 6000 miles (10 000 km) or
6 months - whichever comes sooner
m mRenew engine oil and filter (Section 8)
m mCheck brake pads or shoes for wear (front and rear)
(Section 9)
m mCheck operation of brake fluid level warning indicator
(Section 9)
m mInspect engine bay and underside of vehicle for fluid
leaks or other signs of damage (Section 10)
m mCheck function and condition of seat belts
(Section 11)
m mCheck condition and security of exhaust system
(Section 12)
m mCheck tightness of wheel nuts (Section 13)
m mClean oil filler cap (Section 14)
m mCheck idle speed (where applicable) (Section 15)
m mCheck mixture adjustment (where applicable)
(Section 16)
Every 12 000 miles (20 000 km) or
12 months - whichever comes sooner
m mCheck automatic transmission fluid level (engine hot)
(Section 17)
m mCheck manual gearbox oil level (Section 18)
m mCheck operation of latches, check straps and locks;
lubricate if necessary (Section 19)
m mRenew spark plugs (Section 20)
m mCheck condition and tension of auxiliary drivebelt(s);
adjust or renew as necessary (Section 21)
m mCheck tightness of battery terminals, clean and
neutralise corrosion if necessary (Section 22)
m mCheck engine valve clearances - SOHC only
(Section 23)
m mCheck handbrake mechanism (Section 24)
Every 24 000 miles (40 000 km) or
2 years - whichever comes sooner
m mCheck air cleaner inlet air temperature control
operation (carburettor models) (Section 36)
m mRenew pulse air filter element (1.6 litre CVH)
(Section 37)
m mRenew air cleaner element (Section 38)
m mClean and inspect distributor cap and HT leads
(Section 39)
m mCheck automatic transmission brake band
adjustment (Section 40)
m mRenew fuel filter (fuel-injection models only)
(Section 41)
m mRenew crankcase ventilation vent valve (SOHC and
DOHC) (Section 42)
m mClean radiator matrix and air conditioning condenser
fins (where applicable) (Section 25)
m mCheck air conditioning refrigerant charge (where
applicable) (Section 26)
m mCheck final drive oil level (Section 27)
m mLubricate automatic transmission selector/kickdown
linkage (Section 28)
m mCheck security and condition of steering and
suspension components, gaiters and boots
(Section 29)
m mCheck condition and security of driveshaft joints and
gaiters (Section 30)
m mInspect underbody and panels for corrosion or other
damage (Section 31)
m mInspect brake pipes and hoses (Section 32)
m mClean idle speed control linkage at throttle (where
applicable) (Section 33)
m mRoad test and check operation of ABS (Section 34)
m mCheck crankcase ventilation system (Section 35)
Every 36 000 miles (60 000 km) or
3 years - whichever comes sooner
m mRenew brake hydraulic system seals and hoses if
necessary (Section 43)
m mRenew brake hydraulic fluid (Section 44)
m mRenew camshaft drivebelt (optional on SOHC
models - compulsory on CVH) (Section 45)
m mRenew coolant (Section 46)
Every 12 000 miles (20 000 km) or
12 months - whichever comes sooner
(continued)

Maintenance - component location 1•5
1
Underbonnet view of a 1985 2.0 litre SOHC
fuel injection model
1 Battery
2 Brake servo non-return valve
3 Ignition coil
4 Suspension strut top
5 Fuel filter
6 Air cleaner
7 Airflow meter
8 Fuel pressure regulator
9 Air inlet hose
10 Throttle body
11 Alternator
12 VIN plate
13 Windscreen washer reservoir
14 Coolant expansion tank
15 Oil filler cap
16 Idle speed control valve
17 Inlet manifold
18 Brake fluid reservoir
19 Fusebox
20 Windscreen wiper motor
21 Engine oil level dipstick
Underbonnet view of a 1983 2.0 litre SOHC
carburettor model (air cleaner removed)
1 Brake fluid reservoir
2 Windscreen wiper motor
3 Battery
4 Ignition coil
5 Carburettor
6 Distributor
7 Fuel pressure regulator
8 Thermostat housing
9 Radiator top hose
10 Upper fan shroud
11 Alternator
12 Windscreen washer reservoir
13 Oil filler cap
14 Cooler expansion tank
15 Suspension strut top
16 VIN plate
17 Fusebox

1•6Maintenance - component location
Underbonnet view of a 1990 2.0 litre DOHC
fuel injection model
1 Battery
2 Braking system deceleration-sensitive valve
3 Ignition coil
4 Suspension strut top
5 Air cleaner
6 Plenum chamber
7 Idle speed control valve
8 Distributor
9 Oil filler cap
10 VIN plate
11 Windscreen washer reservoir filler neck
12 Power steering fluid reservoir
13 Coolant expansion tank
14 Manifold absolute pressure (MAP) sensor
15 Brake fluid reservoir
16 Inlet manifold
17 Fuel pressure regulator
18 Fusebox
19 Windscreen wiper motor
Underbonnet view of a 1989 1.8 litre (R2A)
CVH model (air cleaner removed)
1 Battery
2 Suspension strut top
3 Ignition coil
4 Coolant expansion tank
5 Alternator
6 Distributor cap shroud
7 VIN plate
8 Electric cooling fan
9 Radiator top hose
10 Windscreen washer reservoir
11 Fuel vapour separator
12 Thermostat housing
13 Oil filler cap
14 Carburettor
15 Brake fluid reservoir
16 Engine oil level dipstick
17 Windscreen wiper motor
18 Fusebox

Maintenance - component location 1•7
1
Front underside view of a 1990
2.0 GLS model
1 Horns
2 Tie-rod end
3 Tie-rod
4 Gaiter
5 Coolant pump
6 Suspension lower arm
7 Anti-roll bar
8 Starter motor
9 Exhaust downpipes
10 Crossmember
11 Engine sump
12 Oil filter
13 Power steering fluid pump
14 Windscreen washer reservoir
15 Cooling fans
Underbonnet view of a 1992 1.6 litre
CVH model (air cleaner removed)
1 Battery
2 Braking system deceleration-sensitive
valve
3 Suspension strut top
4 Coolant expansion tank
5 Pulse-air filter
6 Vacuum-operated air valve
7 Alternator
8 Cooling fans
9 Oil filler cap
10 Thermostat housing
11 VIN plate
12 Windscreen washer reservoir filler neck
13 Ignition module
14 Pulse-air control solenoid
15 CFI unit
16 Brake fluid reservoir
17 Engine oil level dipstick
18 Manifold absolute pressure (MAP)
Sensor
19 Fusebox
20 Windscreen wiper motor

3Slacken the drain plug about half a turn.
Position the draining container under the drain
plug, then remove the plug completely. If
possible, try to keep the plug pressed into the
sump while unscrewing it by hand the last
couple of turns. As the plug releases from the
threads, move it away sharply so the stream
of oil issuing from the sump runs into the
container, not up your sleeve! Recover the
sealing washer from the drain plug.
4Allow some time for the old oil to drain,
noting that it may be necessary to reposition
the container as the oil flow slows to a trickle.
5After all the oil has drained, wipe off the
drain plug with a clean rag. Check the sealing
washer for condition, and renew it if
necessary. Clean the area around the drain
plug opening, and refit the plug. Tighten the
plug to the specified torque.
6Move the container into position under the
oil filter.
7Using an oil filter removal tool if necessary,
slacken the filter initially, then unscrew it by
hand the rest of the way (see illustration).
Empty the oil from the old filter into the
container, and discard the filter.
8Use a clean rag to remove all oil, dirt and
sludge from the filter sealing area on the
engine. Check the old filter to make sure that
the rubber sealing ring hasn’t stuck to the
engine. If it has, carefully remove it.
9Apply a light coating of clean engine oil to
the sealing ring on the new filter, then screw it
into position on the engine. Tighten the filter
firmly by hand only - do notuse any tools.
Wipe clean the filter and sump drain plug.10Remove the old oil and all tools from
under the car, then lower the car to the
ground (if applicable).
11Remove the oil filler cap and withdraw the
dipstick. Fill the engine, using the correct
grade and type of oil (see “Lubricants and
fluids”). An oil can spout or funnel may help to
reduce spillage. Pour in half the specified
quantity of oil first, then wait a few minutes for
the oil to fall to the sump. Continue adding oil
a small quantity at a time until the level is up to
the lower mark on the dipstick. Finally, bring
the level up to the upper mark on the dipstick.
Insert the dipstick, and refit the filler cap.
12Start the engine and run it for a few
minutes; check for leaks around the oil filter
seal and the sump drain plug. Note that there
may be a delay of a few seconds before the oil
pressure warning light goes out when the
engine is first started, as the oil circulates
through the engine oil galleries and the new oil
filter, before the pressure builds up.
13Switch off the engine, and wait a few
minutes for the oil to settle in the sump once
more. With the new oil circulated and the filter
completely full, recheck the level on the
dipstick, and add more oil as necessary.
14Dispose of the used engine oil safely, with
reference to “General repair procedures”in
the Reference section of this manual.
1Firmly apply the handbrake, then jack up
the front and rear of the car and support it
securely on axle stands (see “Jacking and
vehicle support”).
2For a quick check, the front brake disc pads
can be inspected without removing the front
wheels by inserting a mirror between each
caliper and roadwheel(see illustration).If any
one pad is worn down to the minimum
specified thickness, all four pads (on both
front wheels) must be renewed.
3It is necessary to remove the rear wheels in
order to inspect the rear disc pads. The pads
can be viewed through the top of the caliper
after removing the blanking spring clip(see
illustration).If any one pad is worn down to
the minimum specified, all four pads (on both
rear wheels) must be renewed.4For a comprehensive check, the brake disc
pads should be removed and cleaned. The
operation of the caliper can then also be
checked, and the condition of the brake discs
can be fully examined on both sides. Refer to
Chapter 10 for further information.
5On rear drum brake models, the brake shoe
friction material can be inspected for wear
without removing the roadwheels. Working
beneath the vehicle, prise the plug from the
brake backplate, and using an inspection
lamp or torch, check that the friction material
thickness is not less than the minimum given
in the Specifications(see illustration).If any
one of the shoes has worn below the
specified limit, the shoes must be renewed as
an axle set (4 shoes).
6At the same interval, check the function of the
brake fluid level warning light. Chock the wheels,
release the handbrake and switch on the
ignition. Unscrew and raise the brake fluid
reservoir cap whilst an assistant observes the
warning light: it should come on as the level
sensor is withdrawn from the fluid. Refit the cap.
7On completion, refit the wheels and lower
the car to the ground.
1Visually inspect the engine joint faces,
gaskets and seals for any signs of water or oil
leaks. Pay particular attention to the areas
around the rocker cover, cylinder head, oil
filter and sump joint faces. Bear in mind that
over a period of time some very slight
seepage from these areas is to be expected
but what you are really looking for is any
indication of a serious leak. Should a leak be
found, renew the offending gasket or oil seal
by referring to the appropriate Chapter(s) in
this manual.
2Similarly, check the transmission for oil
leaks, and investigate and rectify and
problems found.
3Check the security and condition of all the
engine related pipes and hoses. Ensure that
all cable-ties or securing clips are in place and
in good condition. Clips which are broken or
missing can lead to chafing of the hoses,
pipes or wiring which could cause more
serious problems in the future.
10Fluid leak check
9Front and rear brake pad/shoe
check
1•10Every 6000 miles or 6 months
8.7 Unscrewing the oil filter
9.3 Disc pads viewed through caliper
inspection hole (roadwheel removed)9.5 Brake shoe inspection hole plug
(arrowed)9.2 Using a mirror to inspect the disc pad
friction material for wear
A Brake disc B Brake disc pads

4Carefully check the condition of all coolant,
fuel, power steering and brake hoses. Renew
any hose which is cracked, swollen or
deteriorated. Cracks will show up better if the
hose is squeezed. Pay close attention to the
hose clips that secure the hoses to the system
components. Hose clips can pinch and
puncture hoses, resulting in leaks. If wire type
hose clips are used, it may be a good idea to
replace them with screw-type clips.
5With the vehicle raised, inspect the fuel
tank and filler neck for punctures, cracks and
other damage. The connection between the
filler neck and tank is especially critical.
Sometimes a rubber filler neck or connecting
hose will leak due to loose retaining clamps or
deteriorated rubber.
6Similarly, inspect all brake hoses and metal
pipes. If any damage or deterioration is
discovered, do not drive the vehicle until the
necessary repair work has been carried out.
Renew any damaged sections of hose or pipe.
7Carefully check all rubber hoses and metal
fuel lines leading away from the petrol tank.
Check for loose connections, deteriorated
hoses, crimped lines and other damage. Pay
particular attention to the vent pipes and
hoses which often loop up around the filler
neck and can become blocked or crimped.
Follow the lines to the front of the vehicle
carefully inspecting them all the way. Renew
damaged sections as necessary.
8From within the engine compartment,
check the security of all fuel hose attachments
and pipe unions, and inspect the fuel hoses
and vacuum hoses for kinks, chafing and
deterioration.
9Where applicable, check the condition of
the oil cooler hoses and pipes.
10Check the condition of all exposed wiring
harnesses.
1Periodically check the belts for fraying or
other damage. If evident, renew the belt.
2If the belts become dirty, wipe them with a
damp cloth using a little detergent only.
3Check the tightness of the anchor bolts and
if they are ever disconnected, make quite sure
that the original sequence of fitting of
washers, bushes and anchor plates is
retained.
With the vehicle raised on a hoist or
supported on axle stands, check the exhaust
system for signs of leaks, corrosion or
damage and check the rubber mountings for
condition and security. Where damage or
corrosion are evident, renew the system
complete or in sections, as applicable, using
the information given in Chapter 4.With the wheels on the ground, slacken each
wheel nut by a quarter turn, then retighten it
immediately to the specified torque.
Remove and clean the oil filler cap of any
sludge build-up using paraffin.
Inspect the vent hose for blockage or
damage. A blocked hose can cause a build-
up of crankcase pressure, which in turn can
cause oil leaks.
Ford VV carburettor
1Ensure that the air cleaner is correctly fitted,
and that all vacuum hoses and pipes are
securely connected and free from restrictions,
then run the engine until it is at normal
operating temperature.
2Stop the engine, and connect a tachometer
and an exhaust gas analyser in accordance
with the manufacturer’s instructions.
3Start the engine and run it at 3000 rpm for
30 seconds, ensuring that all electrical loads
are switched off (headlamps, heater blower
etc), then allow the engine to idle and check
the idle speed and CO content. Note that the
CO reading will initially rise, then fall and finally
stabilise after between 5 and 25 seconds.4If necessary, adjust the idle speed screw to
give the specified idle speed (see
illustration).
5Checking and adjustment should be
completed within 30 seconds of the meter
readings stabilising. If this has not been
possible, repeat paragraphs 3 and 4, ignoring
the reference to starting the engine.
Weber 2V carburettor
Models without stepper motor
6Proceed as described for the Ford VV
carburettor but note the following:
7It is permissible to loosen the air cleaner
securing screws to allow easier access to the
carburettor adjustment screws but ensure
that all vacuum hoses and pipes are securely
connected. For adjustment screw location
(see illustrations).
Models with stepper motor (ESC II
system)
8The idle speed is controlled by the ESC II
module via the stepper motor. The only idle
speed adjustment possible is provided by the
“idle speed adjustment” wire, which can be
earthed to raise the idle speed by 75 rpm. No
other method of idle speed adjustment should
be attempted. If the idle speed is incorrect,
the problem should be referred to a Ford
dealer, as the problem probably lies in the
ESC II module for which special diagnostic
equipment is required.
15Engine idle speed check
14Oil filler cap check
13Roadwheel security check
12Exhaust system check
11Seat belt check
Every 6000 miles or 6 months 1•11
1
15.7b Weber 2V carburettor adjustment
screw locations - 1.6 litre models
A Idle mixture screwB Idle speed screw
15.7a Weber 2V carburettor adjustment
screw locations - 2.0 litre models up to 1985
A Idle speed screwB Idle mixture screw
15.4 Ford VV carburettor adjustment screw
locations
A Idle speed screwB Idle mixture screw
Caution: Refer to the
precautions in Section 1,
Chapter 4, Part A or B (as
applicable), before proceeding.
Before carrying out any carburettor
adjustments, ensure that the ignition
timing and spark plug gaps are set as
specified. To carry out the adjustments an
accurate tachometer and an exhaust gas
analyser (CO meter) will be required.

Steering and suspension
3Check for any abnormalities in the steering,
suspension, handling or road “feel”.
4Drive the vehicle, and check that there are
no unusual vibrations or noises.
5Check that the steering feels positive, with
no excessive “sloppiness”, or roughness, and
check for any suspension noises when
cornering, or when driving over bumps.
Drivetrain
6Check the performance of the engine,
clutch, transmission and driveshafts.
7Listen for any unusual noises from the
engine, clutch and transmission.
8Make sure that the engine runs smoothly
when idling, and that there is no hesitation
when accelerating.9Where applicable, check that the clutch
action is smooth and progressive, that the
drive is taken up smoothly, and that the pedal
travel is not excessive. Also listen for any
noises when the clutch pedal is depressed.
10Check that all gears can be engaged
smoothly, without noise, and that the gear lever
action is not abnormally vague or “notchy”.
Check the operation and
performance of the braking
system
11Make sure that the vehicle does not pull to
one side when braking, and that the wheels
do not lock prematurely when braking hard.
12Check that there is no vibration through
the steering when braking.
13Check that the handbrake operates
correctly, without excessive movement of thelever, and that it holds the vehicle stationary
on a slope.
14Test the operation of the brake servo unit
as follows. With the engine off, depress the
footbrake four or five times to exhaust the
vacuum. Start the engine, holding the brake
pedal depressed. As the engine starts, there
should be a noticeable “give” in the brake
pedal as vacuum builds up. Allow the engine
to run for at least two minutes, and then
switch it off. If the brake pedal is depressed
now, it should be possible to detect a hiss
from the servo as the pedal is depressed.
After about four or five applications, no further
hissing should be heard, and the pedal should
feel considerably firmer.
1Inspect the crankcase ventilation system
for blockage or damage. A blocked hose can
cause a build-up of crankcase pressure,
which in turn can cause oil leaks (see
illustration).
2On carburettor model SOHC engines, clean
the oil filler cap with paraffin and check that
the vent valve is not blocked by pulling it from
the oil separator and loosening the hose clip
(Section 42).
3On CVH engines, check that the oil
separator and mushroom valve are not
blocked, and clean if necessary (see
illustration).
35Crankcase ventilation system
check
SOHC and DOHC carburettor
models
1A vacuum pump will be required to test the
control components.2To check the operation of the air
temperature control, the engine must be cold.
First observe the position of the flap valve
which should be fully closed prior to starting
the engine(see illustration).The position of
the flap can be observed by disconnecting the
cold air inlet hose from the air cleaner spout
and looking into the spout.
3Start the engine and allow it to idle. Check
that the flap is now fully open to admit hot air
from the exhaust manifold shroud. If the flap
does not fully open, stop the engine and
check the vacuum diaphragm unit and heat
sensor as follows (see illustrations).4Working under the base of the air cleaner
body, disconnect the diaphragm unit-to-heat
sensor vacuum pipe at the sensor end, and
connect a vacuum pump to the diaphragm unit.
Apply a vacuum of 100.0 mm (4.0 in) of mercury.
5If the flap opens, then the heat sensor is
faulty and should be renewed. If the flap
remains closed, then the diaphragm unit is
faulty, and a new air cleaner body will have to
be obtained, as the diaphragm unit is not
available separately.
6On completion of the checks, disconnect
the vacuum pump, and reconnect the vacuum
pipe and cold air inlet hose.
36Air cleaner inlet air
temperature control check
1•18Every 24 000 miles or 2 years
35.1 Loosening the crankcase ventilation
hose clip - CVH models
36.3b Air cleaner heat sensor viewed from
inside air cleaner - OHC models36.3a Air cleaner vacuum diaphragm unit -
OHC models
36.2 Air cleaner flap valve operation -
OHC models
A Flap fully open to admit hot air
B Flap fully closed to admit cold air
35.3 Oil separator (1) and mushroom valve
(2) locations in air cleaner - CVH models
Every 24 000 miles (40 000 km) or 2 years