1988 PONTIAC FIERO gas type

6A2-18 2.8 LITER V-6
Installation
Clean sealing surfaces on cylinder case and oil
pan.
Install gasket and attach retaining bolts.
Remove jack and lower engine.
Install motor mount through bolts.
Install starter.
Install exhaust pipes.
Install converter dust cover.
Lower vehicle.
Install fan shroud.
Install distributor cap.
Refill crankcase.
Install air cleaner.
Connect battery.
Start engine, check for leaks.
OIL PUMP (FIGURE 6A2-22)
Removal
1. Remove oil pan as previously outlined.
2. Remove pump to rear main bearing cap bolt and
remove pump and extension shaft.
Disassembly
1. Remove
the pump cover attaching bolts and the
pump cover. Mark gear teeth so they may be
reassembled with the same teeth indexing.
2. Remove the idler gear and the drive gear and
shaft from the pump body.
3. Remove the pressure regulator valve retaining
pin pressure regulator spring and valve.
4. If the pickup screen and pipe assembly need
replacing, mount the pump in a soft-jawed vise
and extract pipe from pump cover. Do not disturb
the pickup screen on the pipe. This is serviced as
an assembly.
Cleaning and lnspection
1. Wash all parts in cleaning solvent and dry with
compressed air.
2. Inspect the pump body and cover for cracks or
excessive wear.
3. Inspect pump gears for damage or excessive wear.
The pump gears and body are not serviced
separately. If the pump gears or body are
damaged or worn, replacement of the entire oil
pump assembly is necessary.
4. Check the drive gear shaft for looseness in the
pump body.
5. Inspect inside of pump cover for wear that would
permit oil to leak past the ends of the gears.
6. Inspect the pickup screen and pipe assembly for
damage to screen or pipe.
7. Check the pressure regulator valve for fit.
Assembly
1. If the pickup screen and pipe assembly was
removed, it should be replaced with a new part.
Loss of press fit condition could result in an air
leak and loss of oil pressure. Mount the pump in
a soft-jawed vise, apply sealer to outside diameter of
swaged end of pipe, and using Tool
J-8369 tap
the pipe in place with a plastic hammer.
NOTICE: Be careful of twisting, shearing or
collapsing pipe while installing in pump.
2. Install the pressure regulator valve and related
parts.
3. Install the drive gear and shaft in the pump body.
4. Install the idler gear in the pump body in the
original orientation.
5. Install cover gasket.
6. Install the pump cover and torque attaching
screws to specifications.
7. Turn drive shaft by hand to check for smooth
operation.
Installation
1. Assemble pump and extension shaft with retainer
to rear main bearing cap, aligning top end of
hexagon extension shaft with hexagon socket
lower end of distributor drive gear.
2. Install pump to rear bearing cap bolt and torque
to specifications.
3. Install oil pan as previously outlined.
ROD CAP AND
Figure 6A2-23 Measuring Connecting Rod Side
Clearance
CONNECTING ROD BEARINGS
Connecting rod bearings are of the precision
insert type and do not utilize shims for adjustment. DO
NOT FILE RODS OR ROD CAPS. If clearances are
found to be excessive, a new bearing will be required.
Service bearings are available in standard size and
.013mm and .026mm undersize for use with new and
used standard size crankshafts.
lnspection and Replacement
1. With oil pan and oil pump removed, remove the
connecting rod cap and bearing.
2. Inspect the bearing for evidence of wear or
damage. (Bearings showing the above should not
be reinstalled.)
3. Wipe both upper and lower bearing shells and
crankpin clean of oil.

6A3-2 V-8 ENGINE
VALVE TRAIN
A very simple ball pivot-type train is used.
Motion is transmitted from the camshaft through the
hydraulic lifter and push rod to the rocker arm. The
rocker arm pivots on its ball and transmits the
camshaft motion to the valve. The rocker-arm ball is
retained by a nut.
HYDRAULIC VALVE LIFTERS
Hydraulic Valve Lifters are used to keep all parts
of the valve train in constant contact.
The hydraulic lifter assembly consists of: a roller,
the lifter body, which rides in the cylinder block boss,
a plunger, a push rod seat, a metering valve, a plunger
spring, a check ball and spring, a check ball retainer
and a push rod seat retainer.
When the lifter is riding on the low point of the
cam, the plunger spring keeps the plunger and push rod
seat in contact with the push rod.
When the lifter body begins to ride up the cam
lobe, the check ball cuts off the transfer of oil from the
reservoir below the plunger. The plunger and lifter
body then rise as a unit, pushing up the push rod and
opening the valve.
As the lifter body rides down the other side of the
cam, the plunger follows with it until the valve closes.
The lifter body continues to follow the cam to its low
point, but the plunger spring keeps the plunger in
contact with the push rod. The ball check valve will then
move off its seat and the lifter reservoir will
remain full.
INTAKE MANIFOLD
The intake manifold for those engines with
carburetors are made of cast iron or aluminum double
level design for efficient fuel distribution. An Exhaust
Gas Recirculation (EGR) port is also cast into the
manifold for the mixture of exhaust gases with the fuel
air mixture.
The intake manifold for those vehicles equipped
with
PFI is a cast aluminum unit. It centrally supports
a fuel rail with
8 fuel injectors.
EXHAUST MANIFOLDS
Two cast iron exhaust manifolds are used to
direct exhaust gases from the combustion chambers to
the exhaust system. The left hand side manifold
receives a heat shield that is used to route heated air
to the air cleaner. for better fuel vaporization during
warm-up.
COMBUSTION CHAMBERS
Combustion Chambers are cast to insure uniform
shape for all cylinders. Spark plugs are located between
the intake and exhaust valves. The contoured wedge
shape of the combustion chamber minimizes the
possibility of detonation, facilitates breathing and
provides swirling turbulence for smooth, complete
combustion.
ENGINE LUBRICATION
Full pressure lubrication through a full flow oil through drilled passages, to the camshaft and
filter, is furnished by a gear-type oil pump. The crankshaft to lubricate the bearings. The valve lifter oil
distributor, driven by a helical gear on the camshaft,
gallery feeds the valve lifters which, through hollow
drives the oil pump. The main oil gallery feeds oil,
push rods, feed the individually mounted rocker arms.

V-8 ENGINE 6A3-15
engine to deliver the power and performance built into
it.
Another important factor is the cooling of the
valve heads. Good contact between each valve and its
seat in the head is imperative to insure that the heat in
the valve head will be properly carried away.
Several different types of equipment are available
for reseating valves seats. The recommendations of the
manufacturer of the equipment being used should be
carefully followed to attain proper results.
Regardless of what type of equipment is used,
however, it is essential that valve guide bores be free
from carbon or dirt to ensure proper centering of pilot
in the guide. Valve seats should be concentric to within
,002" total indicator reading.
VALVES
Valves that are pitted can be refaced to the proper
angle, insuring correct relation between the head and
stem on a valve
refacing mechanism. Valve stems
which show excessive wear, or valves that are warped
excessively should be replaced. When a valve head
which is warped excessively is
refaced, a knife edge will
be ground on part or all of the valve head due to the
amount of metal that must be removed to completely
reface. Knife edges lead to breakage, burning or
pre-ignition due to heat localizing on this knife edge.
If the edge of the valve head is less than 1/32"
(.08mm)
thick after grinding, replace the valve. Several different
types of equipment are available for
refacing valves.
The recommendation of the manufacturer of the
equipment being used should be carefully followed to
attain proper results.
TORSIONAL DAMPER
Removal
1.
Remove drive belts and pulley.
2. Raise vehicle.
3. Remove crankshaft pulley, then remove damper
retaining bolt.
4. Install Tool J-23523 on damper then, turning
puller screw, remove damper.
Installation
NOTICE: The inertial weight section of the
torsional damper is assembled to the hub with a
rubber type material. The installation procedures
(with proper tool) must be followed or movement
of the inertia weight section on the hub will
destroy the tuning of the torsional damper.
1. Inspect the cover seal contact area surface (on
damper) for damage or grooving and coat front
cover seal with engine oil.
2. Place damper in position over key on crankshaft.
3. Pull damper onto crankshaft as follows:
a. Install appropriate threaded end of Tool
J-23523 into crankshaft. Install tool in
crankshaft so that at least
1/2" (13mm) of
thread engagement is obtained.
Fig. 6A3-26 Installing Torsional Damper
b.
Install plate, thrust bearing and nut to
complete tool installation.
c. Pull damper into position as shown in
Figure 6A3-26.
d. Remove tool from crankshaft then install
damper retaining bolt and torque to
specifications.
4. Install crankshaft pulley.
5. Lower vehicle.
6. Install drive belts and adjust to specifications.
CRANKCASE FRONT COVER (FIG. 6A3-27)
Removal
1.
Remove torsional damper as previously outlined.
2. Remove oil pan.
3. Remove water pump as outlined in Section
6B.
4. Remove crankcase front cover attaching screws
and remove front cover and gasket, then discard
gasket.
lnstallation
1. Clean gasket surface on block and crankcase
front cover.

V-8 ENGINE 6A3-23
1. CRANKSHAFT 2. THRUST BEARING
3. MAlN BEARING
4. BEARING CAP 5. REAR MAlN BEARING CAP 6. RETAINER 7. 13-16 N.rn (120-150 IN. LBS.)
8. GASKET
Figure 6A3-42 Crankshaft Oil Seal-Rear Main
Figure 6/43-43 Seal Removal
NOTICE: Care should be taken when removing
the seal so as not to nick crankshaft sealing
surface.
Installation
1. Lubricate the I.D. and O.D. of new seal with
engine oil.
2. Install seal on tool J-35621 (Figure 6A4-44).
3. Thread screws into rear of crankshaft. Tighten
screws with a screwdriver snugly, this is to insure
that the seal will be installed squarely over the
crankshaft.
Figure 6A3-44 Seal Installation
4. Tighten the wing nut until it bottoms.
5. Remove tool from crankshaft.
6. Install transmission.
REAR MAlN SEAL RETAINER/GASKET
Removal
1. Remove oil pan bolts and lower oil pan.
2. Remove transmission as outlined in Section 7.
3. Remove retainer
and seal assembly.
4. Remove gasket.
lnstallation
Whenever the retainer is removed, a new
retainer gasket and rear main seal must be installed.
1. Clean mating surfaces of case and retainer
assembly.
2. (Install new gasket on studs in engine case.
It is not necessary to use any type of sealant to
retain gasket in place.
3. (Install retainer to case bolts, torque bolts
to
10-
13 N-m (90-120 in. Ibs.).
4. Install transmission.
5. Inspect oil pan gasket for damage. Replace
gasket if necessary.
6. Apply
a small amount of 105275
1 or equivalent
to front and rear corners of oil pan.
NOTICE: Only a small amount of sealant is
required. Excessive amounts of sealant may cause a
problem with proper sealing of oil pan.
7. Install oil
pan bolts (Figure
6A4-32).
8. Install rear main seal using tool 5-35621 as
previously outlined.
CONNECTING ROD AND PISTON ASSEMBLIES
Removal
1. Remove oil pan, oil pump and cylinder head as
previously outlined.
2. For
the cylinder being serviced, turn crankshaft
until piston is at the bottom of the stroke. Place
a cloth on top of the piston.

6A3-26 V-8 ENGINE
Fig. 6A3-49 Measuring Ring Groove Clearance
2. Lightly coat pistons, rings
and cylinder walls
with light engine oil.
3. With bearing caps removed, install Tool J-5239
(3/8") on connecting rod bolts.
4. Install
each connecting rod and piston assembly
in its respective bore. Install with connecting rod
bearing tang slots on side opposite camshaft. Use
Tool
5-8037 to compress the rings. Guide the
connecting rod into place on the crankshaft
journal with Tool
5-5239 (3/8"). Use a hammer
handle and light blows to install the piston into
the bore. Hold the ring compressor firmly against
the cylinder block until all piston rings have
entered the cylinder bore.
5. Remove Tool J-5239.
6. Install the bearing caps and torque nuts to
specifications.
Be sure to install new pistons in the cylinders for
which they were fitted, and used pistons in the cylinder
from which they were removed. Each connecting rod
and bearing cap should be marked, beginning at the
front of the engine.
1,3,5 and 7 in the left bank and, 2
4, 6 and 8 in the right bank. The numbers on the
connecting rod and bearing cap must be on the same
side when installed in the cylinder bore. If a connecting
rod is ever transposed from one block or cylinder to
another, new bearings should be fitted and the
connecting rod should be numbered to correspond with
the new cylinder number.
CYLINDER BLOCK
Cleaning and Inspection
1. Wash cylinder block thoroughly in cleaning
solvent and clean all gasket surfaces.
2. Remove oil gallery plugs and clean all oil
passages.
3. Clean and inspect coolant passages in the cylinder
block.
4. Inspect the cylinder block for cracks in the
cylinder walls, coolant jacket, valve lifter bores
and main bearing webs. 5.
Measure the cylinder walls for taper,
out-of-round or excessive ridge at top of ring
travel. This should be done with a dial indicator.
Set the gage so that the thrust pin must be forced
in about
1/4" (6.5mm) to enter gage in cylinder
bore. Center gage in cylinder and turn dial to
"0".
Carefully work gage up and down cylinder to
determine taper and turn it to different points
around cylinder wall to determine the
out-of-round condition. If cylinders were found
to exceed specifications, honing or boring will be
necessary.
Conditioning
The performance of the following operation is
contingent upon engine condition at time of repair.
If the cylinder block inspection indicated that the
block was suitable for continued use except for
out-of-round or tapered cylinders, they can be
conditioned by honing or boring.
If the cylinders were found to have less than
.005"
(.13mm) taper or wear, they can be conditioned with
a hone and fitted with the high limit standard size
piston. A cylinder bore of less then
.005" (. 13mm) wear
or taper may not entirely clean up when fitted to a high
limit piston. If it is desired to entirely clean up the bore
in these cases, it will be necessary to
rebore for an
oversize piston. If more than
.005" (. 13mm) taper or
wear, they should be bored and honed to the smallest
oversize that will permit complete resurfacing of all
cylinders.
When pistons are being fitted and honing is not
necessary, cylinder bores may be cleaned with a hot
water and detergent wash. After cleaning, the cylinder
bores should be swabbed several times with light engine
oil and a clean cloth and then wiped with a clean dry
cloth.
Boring
1. Before using any type boring bar, the top of the
cylinder block should be filed to remove any dirt
or burrs. This is very important. If not checked,
the boring bar may be tilted which would result
in the
rebored cylinder wall not being at right
angles to the crankshaft.
2. The
piston to be fitted should be measured with
a micrometer, measuring at the center of the
piston skirt and at right angles to the piston pin.
The cylinder should be bored to the same
diameter as the piston and honed to give the
specified clearance.
3.
The instructions furnished by the manufacturer
of the equipment being used should be carefully
followed.
Honing
1. When cylinders are to be honed, follow the hone
manufacturer's recommendations for the use of
the hone and cleaning and lubrication during
honing.
2. Occasionally during the honing operation, the
cylinder bore should be thoroughly cleaned and
the piston selected for the individual cylinder
checked for correct fit.

V-8 ENGINE 6A3-27
3. When finish honing
a cylinder bore to fit a piston,
the hone should be moved up and down at a
sufficient speed to obtain very fine uniform
surface finish marks in a cross-hatch pattern of
approximately
45" to 65" included angle. The
finish marks should be clean but not sharp, free
from imbedded particles and torn or folded
metal.
4. Permanently mark
the piston for the cylinder to
which it has been fitted and proceed to hone
cylinders and fit the remaining pistons.
NOTICE: Handle the pistons with care and do not
attempt to force them through the cylinder until
the cylinder has been honed to correct size as this
type piston can be distorted through careless
handling.
5. Thoroughly
clean the bores with hot water and
detergent. Scrub well with a stiff bristle brush and
rinse thoroughly with hot water. It is extremely
essential that a good cleaning operation be
performed. If any of the abrasive material is
allowed to remain in the cylinder bores, it will
rapidly wear the new rings and cylinder bores in
addition to the bearings lubricated by the
contaminated oil, the bores should be swabbed
and then wiped with a clean dry cloth. Cylinder
should not be cleaned with kerosene or gasoline.
Clean the remainder of the cylinder block to
remove the excess material spread during the
honing operation.
Piston Selection
1. Check USED piston to cylinder bore clearance as
follows:
a. Measure
the "Cylinder Bore Diameter"
with a telescope gage
"2-1/2" (64mm) from
top of cylinder bore").
b. Measure
the
"Piston Diameter" (at skirt
across center line of piston pin).
c. Subtract
piston diameter from cylinder bore
diameter to determine "Piston to Bore
Clearance".
d. Determine if piston to bore clearance is in
the acceptable range.
2. If
used piston is not acceptable, check Piston Size
Chart and determine if a new piston can be
selected to fit cylinder bore within the acceptable
range.
3. If
cylinder bore must be reconditioned, measure
new piston diameter (across center line of piston
pin) then hone cylinder bore to correct clearance
(preferable range).
4. Mark the piston to identify the cylinder for which
it was fitted.
OIL FILTER BYPASS VALVE
Inspection and Replacement
With the oil filter removed, check the spring and
fibre valve for operation. Inspect for a cracked or
broken valve. If replacement is necessary, the oil filter
adapter and bypass valve assembly must be replaced as an
assembly. Clean valve chamber in cylinder block
thoroughly. Torque retaining screws to specifications.
ENGINE ASSEMBLY
Removal
1. Disconnect battery.
2. Remove air cleaner.
3. Remove hood.
4. Drain radiator.
5. Remove lower radiator hose.
6. Remove upper fan shroud.
7. Remove upper radiator hose and coolant
recovery hose.
8. Remove transmission cooler lines.
9. Remove radiator.
10. Remove fan assembly.
1 1. Remove heater hoses.
12. Disconnect
carburetor linkage, includes cruise
control detent cable.
13. Remove vacuum brake booster line.
14. Remove
distributor cap and lay wiring aside.
15. Disconnect necessary wires and hoses.
16. Remove power steering
pump and lay aside.
17. Raise vehicle.
18. Remove exhaust
pipes at exhaust manifold.
19. Remove dust cover.
20. Remove converter bolts.
2 1. Disconnect starter wires.
22. Remove bell housing bolts.
23. Remove
motor mount through bolts.
24. Disconnect fuel lines
at fuel pump.
25. Lower vehicle.
26. Support transmission.
27. Remove
A.I.R./Converter pipe bracket.
28. Remove engine, include removing wire
from
bracket at rear left of engine.
Installation
1. Position engine
assembly in vehicle.
2. Attach
motor mount to engine brackets and
lower engine in place.
3. Remove engine lifting device.
4. Remove transmission floor jack.
5. Raise vehicle on hoist.
6. Install mount "through" bolts. Torque to
specifications.
7. Install bell housing bolts. Torque to
specifications.
8. On vehicles with automatic transmissions, install
I
converter to flywheel attaching bolts. Torque to
specifications.
9. Install flywheel splash shield of converter
housing cover as applicable. Torque attaching
bolts to specifications.
I
10. Install starter wires.
1 1. Connect fuel lines.
12. Connect exhaust pipe at manifold.
13. Lower vehicle on hoist.
14. Reinstall power steering pump, if so equipped.
15. Connect necessary wires and hoses.

ENGINE COOLING 6B-1
SECTION 6B
NE COOL
General Description ................................ 6B- 1 Off-Vehicle Leak Testing ............................... 6B-9
Radiator
...................................................... 6B- 1 Repairable Leaks ........................ ... .......... 6B- 10
Radiator Cap
......................... .. ............... 6B- 1 Repair Methods ................................................ 6B- 10
Recovery Bottle ......................................... 6B-2 Cooling Fin Removal ................................ 6B- 10 - ............................................. Fans ............................................................... 6B-2 Tube Blocking 6B- 1 1 ............ Header Repair ....................... .... 6B- 1 1 Temperature Switch ..................................... 6B-2 General Core Repair 6B- 1 1 ....................................
........................... Coolant Temperature Fan Switch ................ 6B-2 Tank
Gasket ~eik Repair 6B- 12
................... Thermostat .. 6B-3 Oil
Cooler Gasket Replacement
6B- 13 ............... ................................
...........................................................
Coolant Recovery System 6B-3 Recore 6B- 14 ............................. Special Tools ..................................................... 6B- 14 Diagnosis ..................................................... 6B-3
.............................. ..................................... Service Procedures 6B-3 On-Vehicle Service 6B-14
Cooling System Care
............................... 6B-3 Thermostat ....................................... 6B-14
Draining and Refilling the Cooling Electric Cooling Fan ............................. 6B-15
System
................................................... 6B-7 Water Pump .................... .... ......... 6B-15
Drive Belt
...................... .. .......................... 6B-7 Coolant Recovery Bottle ........................ 6B-16
.......................................... Aluminum Radiator Service .................... 6B-8 Radiator 6B-17
Diagnosis .................................................... 6B-8
Leak Testing
.............................................. 6B-8
On-Vehicle Pressure Testing
...................... .... 6B-9
GENERAL DESCRIPnIBN
The cooling system maintains engine temperature
5" below the filler neck which reads, "Important - for
at an efficient level during all engine operating repair see Harrison Service Manual". Service
conditions. When the engine is cold the system cools procedures for the aluminum plastic radiator are
slowly, or not at all, to allow the engine to warm up described in that manual and in this section.
quickly.
The cooling system includes a radiator and
Radiator Cap
recovery sub-system, cooling fan, thermostat and
housing, water pump, and drive belts.
Operation of the cooling system requires proper
functioning of all components. Coolant is drawn from
the radiator by the water pump and circulated through
water jackets in the engine block, intake manifold, and
cylinder
head(s), and then directed back to the radiator
where it's cooled.
This system directs some coolant through hoses
to the heater core, to provide for heating and
defrosting. A recovery bottle is connected to the
radiator to recover coolant displaced by expansion
from high temperatures and maintain correct coolant
level. As the coolant cools and contracts it is drawn
back into the radiator by vacuum.
RADIATOR
A cross-flow radiator is used on all models. Tanks
in this type radiator are located to the right and left of
the core, instead of above and below.
Radiators used with automatic transmissions
have oil coolers with inlet and outlet fittings for
transmission fluid circulation. Cars with manual
transmissions use radiators without oil coolers.
Vehicles equipped with air conditioning use a radiator
with extra cooling capability.
An aluminum-plastic radiator, used on some
models, can be identified by a note on the outlet tank A pressure-vent
cap is used on the cross-flow
radiator to allow a buildup of
103 kPa (15 psi) in the
cooling system. This pressure raises the boiling point
of coolant to approximately 125°C (262°F) at sea level.
Do not remove radiator cap to check engine
coolant level; check coolant visually at the
see-through coolant reservoir. Coolant should
be added only
to the reservoir.
CAUTION: As long as there
is
pressure in the cooling system, the
temperature can be considerably
higher than the boiling temperature
of
the solution in the radiator without
causing the solution to boil. Removal
of the radiator cap while engine is hot
and pressure is high will cause
the
solution to boil instantaneously and
possibly with explosive
force, spewing
the solution over engine, fenders and
person removing cap. If the solution
contains flammable antifreeze, such
as alcohol (not recommended for use
at any time), there is also the
possibility
of causing a serious fire.
The pressure-type radiator filler cap contains a
blow off or pressure valve and a vacuum or
atmospheric valve (Figure
1). The pressure valve is
held against its seat by a spring of pre-determined

BB-2 ENGINE COOLING
strength, which protects the radiator by relieving
pressure if it exceeds design limits. The vacuum valve
is held against its seat by a light spring, which permits
opening of the valve to relieve vacuum created in the
system when it cools off and which otherwise might
cause the radiator to collapse.
VACUUM RELIEF PRESSURE RELIEF
Fig. 1 Pressure-Type Radiator Cap
The radiator cap is designed to discourage
inadvertent removal. The finger grips have been
removed so the cap is round in shape. It also must be
pushed downward before it can be removed. A rubber
asbestos gasket is added to the diaphragm spring at the
top of the cap. Embossed on the cap is a caution against
its being opened and arrows indicating the proper
closed position.
Every vehicle has a radiator cap. Also,
J, N and
P Series vehicles with 2.5L engines have a thermostat
housing cap. For these engines, add coolant through
the thermostat housing (with the thermostat and cap
removed).
Recovery Bottle
A "see-through" plastic reservoir, similar to the
familiar windshield washer jar, is connected to the
radiator by a hose. As the car is driven, the coolant is
heated and expands. The portion of the fluid displaced
by this expansion flows from the radiator into the
recovery bottle. When the engine is stopped and the
coolant cools and contracts, the displaced coolant is
drawn back into the radiator by vacuum. Thus, the
radiator is kept filled with coolant to the desired level
at all times, resulting in increased cooling efficiency.
Coolant level should be between "ADD" and
"FULL"
marks on recovery bottle. These marks are
approximately two quarts apart so that a
50/50
mixture can be added (one quart of ethylene glycol
anti-freeze and one quart of water).
FAN
Electric Fan
Fans range in sizes from 290mm (11.6 in) to
422mm (16.9 in) with 4 to 7 blades to aid air flow
through the
radiator/condenser. The fan is driven by
an electric motor which is attached to the radiator
support.
The fan motor is activated by a coolant
temperature switch. If the vehicle is equipped with
Fig. 2 Coolant Recovery Bottle
A/C, a second switch can activate the circuit,
depending upon
A/C compressor head pressure to the
condenser.
CAUTION: If a fan blade is bent or
damaged in any way, no attempt
should be made to repair and reuse the
damaged part.
A bent or damaged fan
assembly should always be replaced
with a new fan assembly. It is
essential that fan assemblies remain
in proper balance and proper balance
cannot be assured once a fan
assembly has been bent or damaged.
A fan assembly that is not in proper
balance could fail and fly apart during
subsequent use, creating an
extremely dangerous condition.
The majority of non-A/C cars use a fan with four
blades which are unevenly spaced and have curled tips
to provide minimum noise.
A fan shroud is used to
prevent recirculation of air around the fan on most
cars.
Thermostatically Controlled Fluid Clutch Fan
A thermostatically controlled fluid clutch fan is
used on some air conditioned vehicles. It operates only
when additional air flow is required to reduce radiator
coolant temperatures. This clutch is of a simple,
functional design. It is made of lightweight metal filled
with silicone oil and is hermetically sealed. The finned
(rear) housing contains a hub assembly (secured to the
housing bearing) which attaches to the engine water
pump. Four bosses with tapped holes in the rear face
provide for attachment of the engine fan. The front
surface of the housing has six deep circular grooves
which index with six matching bosses on the rear face
of a floating clutch. A separator plate and front cover,
with thermostatic coil control, complete the clutch
assembly.
During periods of operation when radiator
discharge air temperature is low, below approximately
66°C (150°F), the clutch limits the fan speed to
800- 1400 rpm. In this position, the clutch is disengaged