1988 PONTIAC FIERO oil temperature

MAINTENANCE AND LUBRICATION OB-5
Throttle linkage inspection -- Inspect for inter-
ference, binding, damaged or missing parts.
Engine drive belts inspection - Inspect all
belts for cracks, fraying and wear. Adjust or replace as
needed.
Rear axle service (if equipped) - Check gear
lubricant level and add if needed. For cars equipped with a
limited slip rear axle, fluid does not require changing
(except Caprice and Corvette
- change fluid and required
additive at first
7,500 miles (12 500 km). See your
Owner's Manual or "Recommended Fluids
& Lubricants
Chart" in this section.
IF YOU USE YOUR GAR TO PULL A TRAILER,
CHANGE GEAR LUBRICANT EVERY 7,500 MILES
(12 500 KM).
NOTICE: A large loss in this system may indicate a
problem. Have it inspected and repaired at once.
Power antenna - Clean and then lubricate power
antenna mast. The proper lubricant as shown in Figure
OB-2 should be used.
AT LEAST ONCE A YEAR
Lap and shoulder belts condition and opera-
tion
- Inspect belt system, including webbing, buckles,
latch plates, retractors, guide loops and anchors.
Moveable head restraint operation - On cars
with moveable restraints, make sure restraints stay in the
desired position. (See adjustment instructions in your
Owner's Manual.)
Seatback latch and recliner operation on
cars equipped
with recliner seat --- Be sure seat-
backs latch on those cars with folding seats using mechan-
ical latches. Make sure the recliner is holding by pushing
and pulling on the top of the
seatback while it is reclined.
See your Owner's Manual for seat operating information.
Spare tire and jack storage- Be alert to rattles
in rear of car. Make sure the space tire, all jacking equip-
ment, any tire inflator and any covers or doors are securely
stowed at all times. Oil jack ratchet or screw mechanism
after each use.
Key lock service - Lubricate key lock cylinder at
least annually.
Body lubrication service - Lubricate all body
door hinges including the tailgate or hatchback lid (if
equipped). Also lubricate the body hood, fuel door and
rear compartment hinges and latches including interior
glove box and counsel doors, and any folding seat
hardware.
"Fansmissionltransaxle neutral or clutch
starl switch operation
CAUnON: Before pedorming the follow-
ing safety switch check, be sure to have
enough room around the car. Then, firmly
apply both the parking brake (see your
Owner's Manual for procedure) and the
regular brakes. Do not use the accelerator pedal.
If the engine
starls, be ready to turn
off the ignition promptly. Take these pre-
cautions because the car could move
without warning and possibly cause per-
sonal injury or properly damage. On auto-
matic transmissionltransaxle cars, try to
starl the engine in each gear. The starler
should crank only in "Park" or "Neutral."
On manual transmissionltransaxle cars,
place the
shiR lever in "Neutral," push the
clutch halfway and try to starl. The starler
should crank only when the clutch is fully
depressed.
Steering column lock operation
- While
parked, try to turn key to "Lock" in each gear range. The
key should turn to "Lock" only when gear is in "Park" on
automatic or "Reverse" on manual
transmissionltransax-
le. On cars with key release lever, try to turn key toULock"
without depressing the lever. The key should turn to
"Lock" only with the key lever depressed. On all vehicles,
the key should come out only in "Lock."
Parking brake and transmissionltransaxle
"Park" mechanism operation
CAUT1ON:Before checking the holding
ability of the parking brake and automatic
transmissionltransaxle "Park" mecha-
nism, park on a fairly steep hill with
enough room for movement in the down-
hill direction. To reduce the risk of person-
al injury or property damage, be prepared
to apply the regular brakes promptly if the
car begins to move.
To check the parking brake, with the engine running and
transmission/transaxle in "Neutral." slowly remove foot
pressure from the regular brake pedal (until the car is held
by only the parking brake).
To check the automatic transmissionltransaxle "Park"
mechanism holding ability, release all brakes after shift-
ing the transmissionltransaxle to "Park."
ljnderbody flushing - At least every spring,
tlush from the underbody with plain water any corrosive
materials used for ice and snow removal and dust control.
Take care to thoroughly clean any areas where mud and
other debris can collect.
Sediment packed in closed areas
of the vehicle should be loosened before being flushed.
Engine cooling system service - Inspect
coolant and freeze protection. If dirty or rusty, drain, flush
and refill with new coolant. Keep coolant
at the proper
mixture as specified in your Owner's Manual. This pro-
vides proper freeze protection. corrosion inhibitor level
and engine operating temperature. Inspect hoses and re-
place if cracked. swollen or deteriorated. Tighten hose
clamps. Clean outside of radiator and air conditioning
condensor. Wash radiator filler cap and neck.
To help
ensure proper operation. a pressure test of both the cooling
system and cap is also recommended. (See maintenance
schedule charts in Figure
OB-l for the recommended
coolant change interval.)

AIR CONDITIONING 1B-1
SECTION 1B
R COND
When performing air conditioning diagnosis on vehicles equipped with a catalytic converter, it will be necessary to
WARM the engine to a NORMAL operating temperature BEFORE attempting to idle the engine for periods greater
than five
(5) minutes. Once the engine attains normal idle, diagnosis and adjustments can be made.
CONTENTS
.................. General Description .................................. 1B-1 Accumulator Assembly Service .1B-19
.......................... C.C.O.T. A!C System ................................ 1B-1 On-Vehicle Sewice ..... 1B-20
....................................... System Components - Functional ................. 1B-2 Blower Motor .1B-20
..................................... System Components - Control ..................... 1B-3 Hi-Blower Relay 1B-20
...................................... Relays and Switches ................................... 1B-3 Blower Resistor 1B-20
Diagnosis ................................................. 1B-5 Controller, Blower Switch or Vacuum
................................................ Testing the Refrigerant System ...................... 1B-5 Valve .lB-20
Insufficient Cooling "Quick-Check Temperature Control Cable ....................... .1B-20
.................................... Procedure.. ............................................. 1B-5 Vacuum
Harness .lB-20
C.C.O.T. A/C System Diagnostic Control Wiring Harness ........................... .1B-20
..... ................................. Procedure.. ............................................. 1B-8 Heater
Core .. .lB-21
................................ Leak Testing ........................................... 1B-12 Lower Heater Outlet 1B-21
............................... Service Procedures ................................. .1B-12 Heater Module Case .lB-21
.......................... O-Ring Replacement ................................ .1B- 12 Pressure Cycling Switch .1B-21
....................................... Handling Refrigerant- 12 ............................ .1B- 13 Vacuum Tank .lB-21
Discharging, Adding Oil, Evacuating Liquid Line .......................................... .1B-23
and
Charging Procedures - AIC Accumulator ......................................... .1B-23
.................................... Systems .............................................. .1B-14 Evaporator Core .1B-24
In-Line Air Conditioning Evaporator Case .................................... .1B-24
.......................................... Filter
Installation.. .................................. .1B- 18 Compressor .lB-24
.............................................
................ Expansion Tube (Orifice) Service .1 B- 19 Condenser IB-24
GENERAL DESCRIPTION
All engines are equipped with a fixed displace- evaporator temperature. The pressure cycling switch
ment (R-4) air conditioning compressor. This
com- is the freeze protection device in the system and
pressor may cycle on and off under normal air
senses refrigerant pressure on the suction side of the
conditioning demand. system. This switch is located on a standard
Schrader- -
All air conditioning systems that use the fixed
displacement R-4 compressor are referred to as
C. C.O.T. (Cycling Clutch, Orifice Tube) type sys-
tems. This is the same system that has been used on
all General Motors vehicles in the past several years.
The C.C.O.T. NG System
The Cycling Clutch Orifice Tube (C.C.O.T.)
refrigeration system is designed to cycle a compressor
on and off to maintain desired cooling and to prevent
evaporator freeze. Passenger compartment comfort is
maintained by the temperature lever on the controller.
Control of the refrigeration cycle (on and off
operation of the compressor) is done with a switch
which senses low-side pressure as an indicator of type
valve low-side fitting. During air temperatures
over 10°C
(50°F), the equalized pressures within the
charged
A/C system will close the contacts of the
pressure switch. When an air conditioning mode
(max, norm, bi-level, defrost) is selected, electrical
energy is supplied to the compressor clutch coil. AS
the compressor reduces the evaporator pressure
to
approximately 175 kPa (25 psi), the pressure switch
will open, de-energizing the compressor clutch.
As
the system equalizes and the pressure reaches approxl-
mately 315 kPa (46 psi), the pressure switch contacts
close, re-energizing the clutch coil. This cycling
coy
tinues and maintains average evaporator discharge air
temperature at approximately 1°C (33°F). Because of
this cycling, some slight increases and decreases of
engine speedlpower may be noticed under certain con-
ditions. This is normal as the system is designed
to
cycle to maintain desired cooling, thus preventing
evaporator freeze-up.

18-2 AIR CONDITIONING
SYSTEM GONIPONENE - FFUNCnIONAL
Compressor
All compressors are belt driven from the engine
crankshaft through the compressor clutch pulley. The
compressor pulley rotates without driving the com-
pressor shaft until an electromagnetic clutch coil is
energized. When voltage is applied to energize the
clutch coil, the clutch plate and hub assembly is
drawn rearward toward the pulley. The magnetic
force locks the clutch plate and pulley together as one
unit to drive the compressor shaft.
As the compressor shaft is driven, it compresses
the low-pressure refrigerant vapor from the evaporator
into a high-pressure, high-temperature vapor. Carried
with the refrigerant is the refrigerant oil which is used
to lubricate the compressor. Complete compressor
overhaul procedures can be found in Section
ID of the
General Service Manual.
Pressure Relief Valve
The compressor is equipped with a pressure
relief valve which is placed in the system as a safety
factor. Under certain conditions, the refrigerant on the
discharge side may exceed the designed operating
pressure. To prevent system damage, the valve is
designed to open automatically at approximately
3036
kPa (440 psi). Conditions that might cause this valve
to open (defective high pressure cut-off switch, inop-
erative electric cooling fan, etc.) should be corrected,
and the refrigerant oil and refrigerant should be
replaced as necessary.
A muffler is used on some refrigerant systems to
reduce compressor noises from high or low pressure
vibrations.
Condenser Gore
The condenser assembly in front of the radiator
is made up of coils which carry the refrigerant TO
cooling fins to provide rapid transfer of heat. The air
passing through the condenser cools the high-pressure
refrigerant vapor causing it to condense to a liquid.
Expansion (Orifice) Tube
The plastic expansion tube, with its mesh screen
and orifice, is located in the evaporator inlet pipe at
the liquid line connection. It provides a restriction to
the high-pressure liquid refrigerant in the liquid line,
metering the flow of refrigerant to the evaporator as a
low-pressure liquid. The expansion tube and orifice
are protected from contamination by filter screens on
both inlet and outlet sides. The tube is serviced only
as a replacement assembly.
When the engine is turned "OFF" with the
A/C
system operating, the refrigerant in the system will
flow from the high-pressure side of the expansion tube (orifice) to the low-pressure side until the pressure
is
equalized. This may be detected as a faint sound of
liquid flowing (hissing) for 30 to
60 seconds and is a
normal condition.
Evaporator Gore
The evaporator is a device which cools and
dehumidifies the air before it enters the car. High-
pressure liquid refrigerant flows through the expan-
sion tube (orifice) into the low-pressure area of the
evaporator. The heat in the air passing through the
evaporator core is transferred to the cooler surface of
the core, thereby cooling the air. As the process of
heat transfer from the air to the evaporator core sur-
face is taking place, any moisture (humidity) in the air
condenses on the outside surface of the evaporator
core and is drained off as water.
Accumulator
5-INTERNAL TUBE
2-REFRIGERANT 6-DESICCANT BAG
VAPOR INLET ASSEMBLY
7-FILTER ASSEMBLY
8-OIL BLEED HOLE
LOCATION IN TUBE
520004-1 8
Figure 1 Accumulator - Interior Parts
Connected to the evaporator outlet pipe, the
sealed accumulator assembly acts as a refrigerant stor-
ing container receiving vapor and some liquid and
refrigerant oil from the evaporator.
At the bottom of the accumulator is the desic-
cant which acts as a drying agent for moisture that
may have entered the system. An oil bleed hole is also
located near the bottom of the accumulator outlet pipe
to provide an oil return path to the compressor.

AIR CONDITIONING 1 B-3
A low-side pressure Schrader valve service fit-
ting is located near the top of the accumulator. A
similar Schrader fitting may be provided for mounting
the pressure cycling switch. It is not necessary to dis-
charge the system to replace the switch. The accumu-
lator is serviced only as a replacement assembly.
Heater Core
The heater core heats the air before it enters the
car. Engine coolant is circulated through the core to
heat the outside air passing over the fins of the core.
The core is functional at all times (no water valve) and
may be used to temper conditioned air in
A/C mode,
as well as heat or vent mode.
SYSTEM COMPONENTS --- CON"FOL
Controller
The operation of the A/C system is controlled by
the switches and the lever on the control head. The
compressor clutch and blower are connected electri-
cally to the control head by a wiring harness. The
blower circuit is open in the off mode and air flow is
provided by the four blower speeds available in the
remaining modes. Cooled and dehumidified air is
available in the max, normal, bi-level and defrost
modes.
Temperature is controlled by the position of the
temperature lever on the control head. A cable con-
nects this lever to the temperature door which controls
air flow through the heater core. As the temperature
lever is moved through its range of travel, a sliding
clip on the cable at the temperature valve connection
should assume a position assuring that the temperature
door will seat in both extreme positions. Temperature
door position is independent of mode selection. The
temperature cable attaches to the right side of the air
conditioning module. The temperature door on some
models is controlled electrically, thereby eliminating
the need for the temperature cable.
The electric engine cooling fan on some cars is
not part of the
A/C system; however, the fan is
operational any time the
A/C control is in Max.,
Norm, or Bi-Level modes. Some models provide for
engine cooling fan operation when the controller is in
the defrost mode. This added feature is part of the
A/C
controller function and is aimed at preventing exces-
sive compressor head temperatures. It also allows the
A/C system to function more efficiently. On some
models during road speed (above
35 mph) conditions
when air flow through the condenser coil is adequate
for efficient cooling, the engine cooling fan will be
turned off. The operation of the cooling fan is con-
trolled by the ECM through the cooling fan relay.
Complete wiring diagrams and diagnosis for the
AIC Electrical System are in Section 8A. Section 8A
also contains additional diagnostic information
regarding air flows and vacuum logic.
Vacuum Lines
Vacuum lines are molded to a connector which
is attached to a vacuum control switch on the control
head assembly.
In case of leakage or hose collapse, it will not be
necessary to replace the entire harness assembly.
Replacement can be made by cutting the hose and
inserting a plastic connector. If an entire hose must be
replaced, cut all hoses off at the connector and then
attach hoses directly to the control head vacuum
switch. (NOTE: The Fiero uses an electric motor to
control mode selection. Therefore, it will not have a
vacuum harness.
)
Vacuum Tank
During heavy acceleration, the vacuum supply
from the carburetor drops. A check valve in the vac-
uum tank maintains vacuum so that, under load condi-
tions, vacuum will be available for continuous use.
REWVS AND SWITCHES
High-Pressure Compresssr Gut-OFF Switch
The high-side, high-pressure cut-off switch in
the rear head of the compressor is a protective device
intended to prevent excessive compressor head pres-
sures and reduce the chance of refrigerant escape
through a safety relief valve. Normally closed, this
switch will open the circuit at a high-side pressure of
approximately 2700
kPa (430 psi 9 20 psi) and
reclose the circuit at approximately 1379 kPa (200 psi
9 50 psi).
Lsw-Pressure Cut-On Switch
Compressor protection is provided on some cars
by a low-pressure cut-off switch which will open in
the event of a low-charge condition. This switch can
be located in the liquid line or in the rear head of the
compressor. This switch will also keep the compres-
sor from running during cold weather.
Pressure eyesing Switch
The refrigeration cycle (on and off operation of
the compressor) is controlled by a switch which
senses the low-side pressure as an indicator of evapo-
rator temperature. The pressure cycling switch is the
freeze protection device in the system and senses
refrigerant pressure on the suction side of the system.
This switch is located on a standard Schrader-type
valve low-side fitting. This switch also provides com-
pressor cut-off during cold weather.
Additional compressor protection results from
the operating characteristics of the low-side pressure
cycling system. If a massive discharge occurs or the
orifice tube becomes plugged, low-side pressures
could be insufficient to close the contacts of the pres-
sure switch. In the event of a low charge, insufficient
cooling accompanied by rapid compressor clutch
cycling will be noticed at high air temperatures.

AIR GONDlTlONlNG 1B-7
REFRIGERANT - 12
PRESSURE - TEMPERATURE
RELATIONSHIP
The table below indicates the pressure of Refri-
gerant - 12 at various temperatures. For in-
stance, a drum of Refrigerant at a temperature
of
&!OF (26.%C) will have a pressure of 84.1 PSI
(579.9 kPa). If it is heated to 129 F (51.%C), the
pressure will increase to 167.5 PSI (1154.9
kPa). It also can be used conversely to deter-
mine the temperature at which Refrigerant - 12 boils under various pressures. For example,
at a pressure of 30.1 PSI (207.5 kPa), Refriger-
ant - 12 boils at 32F ((PC).
O(ATM0SPHERIC PRESSURE)
2.4
4.5
Figure 7 A/C System Performance Test

18-14 AIR CONDITIONING
HANDLING OF REFRIGERANT LINES AND
FI-INGS
Tighten all tubing connections as shown in
torque chart (Figure 13). INSUFFICIENT OR
EXCESSIVE TORQUE WHEN TIGHTENING CAN
RESULT IN LOOSE JOINTS OR DEFORMED
JOINT PARTS. Either condition can result in refrig-
erant leakage.
All metal tubing lines should be free of dents or
kinks to prevent loss of system capacity due to line
restriction.
@ The flexible hose lines should never be bent to a
radius of less than four (4) times the diameter of
the hose.
@ The flexible hose lines should never be allowed
to come within a distance of
63.5mm (2-112") of
the exhaust manifold.
@ Flexible hose lines should be inspected regularly
for leaks or brittleness and replaced with new
lines if deterioration or leaking is found.
@ When disconnecting any fitting in the refrigera-
tion system, the system must first be discharged
of all Refrigerant- 12. Proceed very cautiously
regardless of gauge readings. Open very slowly,
keeping face and hands away so that no injury
can occur if there happens to be liquid
Refriger-
ant-12 in the line. If pressure is noticed when
fitting is loosened, allow it to bleed off as
described under DISCHARGING, ADDING
OIL, EVACUATING AND CHARGING PRO-
CEDURES FOR
A/C SYSTEMS.
@ In the event any refrigerant line is opened to the
atmosphere, it should be immediately capped or
taped to prevent entrance of moisture and dirt,
which can cause internal compressor wear or
plugged lines, in the condenser and evaporator
core and expansion (orifice) tubes or compressor
inlet screens.
@ The use of the proper wrenches when making
connections on O-ring fittings is important. The
opposing fitting should always be backed up
with a wrench to prevent distortion of connecting
lines or components. When connecting the flexi-
ble hose connections, it is important that the
swaged fitting and the flare nut, as well as the
coupling to which it is attached, be held at the
same time using three
(3) different wrenches to
prevent turning the fitting and damaging the
ground seat.
@ O-rings and seats must be in perfect condition. A
burr or piece of dirt may cause a refrigerant leak.
When replacing the O-ring, first dip it in clean
525 viscosity refrigeration oil.
MAINTAINING CHEMICAL STABILITY IN
THE
REFRIGERATION SYSTEM
The efficient operation and life of the air condi-
tioning system is dependent upon the chemical stabil-
ity of the refrigeration system. When foreign materials, such as
dirt, air, or moisture, contaminate
the refrigeration system, they will change the stability
of the Refrigerant-12 and 525 viscosity compressor
oil. They will also affect pressure-temperature rela-
tionship, reduce efficient operation and possibly cause
interior corrosion and abnormal wear of moving parts.
The following general practices should be
observed to insure chemical stability in the system:
1. Before disconnecting a refrigerant connection,
wipe away any dirt or oil at and near the connec-
tion to reduce the possibility of dirt entering the
system. Both sides of the connection should be
capped, plugged or taped as soon as possible to
prevent the entry of dirt, foreign material and
moisture.
2. Keep tools clean and dry. This includes the
manifold gauge set and replacement parts.
3. When adding 525 viscosity refrigerant oil (see
ADDING OIL in the DISCHARGING,
ADDING OIL, EVACUATING AND
CHARGING PROCEDURES FOR
AIC SYS-
TEMS, the transfer device and container should
be clean and dry to assure that refrigeration oil
remains as moisture-free as possible.
4. When it is necessary to "open" an
AIC system,
have everything needed ready and handy so that
as little time as possible will be required to per-
form the operation. Do not leave the
AIC system
open any longer than is necessary.
5. Any time the
A/C system has been "opened," it
should be properly evacuated before recharging
with Refrigerant- 12 according to the DIS-
CHARGING, ADDING OIL, EVACUATING
& CHARGING PROCEDURES FOR AIC
SYSTEMS.
All service parts are dehydrated and sealed
prior to shipping. They should remain sealed until just
prior to making connections. All parts should be at
room temperature before uncapping. (This prevents
condensation of moisture from the air entering the
system.) If, for any reason, caps are removed but the
connections are not made, parts should be resealed as
soon as possible.
DISCHARGING, ADDING OIL,
EVACUATING AND CHARGING
PROCEDURES FOR NC SYSTEMS
The refrigerant system may be discharged,
evacuated and charged using air conditioning service
charging station J-23500-01 or equivalent, or the
manifold and gauge set
5-23575-01 and 420ml (14
oz.) disposable cans of Refrigerant-12 (Figure 16).
Charging lines from the charging station or
manifold and gauge set require the use of gauge
adapters to connect to the system service fitting.
A
straight gauge adapter 5-5420 and a 90" angle gauge
adapter
5-9459 are available (see A/C Special Tools).
Always wear goggles and wrap a clean cloth
around fittings and connections when doing work that

R-4 AIR CONDITIONING COMPRESSOR OVERHAUL 1 Dl-17
2. Align
the new Main Bearing and the Bearing
Installer
5-24895 squarely with the bearing bore
of the Front Head and drive the bearing into the
Front Head. The Installer J-24895 must seat
against the Front Head to insert the bearing to
the proper clearance depth.
Fig. 47 Installing Main Bearing
3. Assemble the Front Head to the cylinder, using
a new O-ring as described in FRONT HEAD
replacement procedure.
4. Evacuate and charge the refrigerant system
according to the directions in Section
1B.
SHELL AND O-RINGS
Fig. 48 thru 50
Remove or Disconnect
1. Discharge the refrigerant system according to the
directions in Section
1B.
2. Thoroughly clean exterior of compressor to
prevent dirt from getting into compressor during
shell removal.
3. Remove the Clutch Plate and Hub assembly as
described in CLUTCH PLATE AND HUB
removal procedures.
4. Perform Steps 1 through 4 of CLUTCH ROTOR
AND BEARING removal procedure but do not
loosen or remove the pulley rim mounting screws
so as to remove the Clutch Rotor and Bearing,
Clutch Coil and Pulley Rim as a total assembly.
Be careful not to drop the Puller Guide J-25031
when removing the assembly.
5. Pry the shell-retaining strap away from the
cylinder and position the strap high enough to
clear the cylinder as the Shell is removed.
6. Remove Compressor Holding Fixture J-25008-A,
and reverse Holding Fixture with step block
protrusions engaging the compressor Shell.
Install the medium-length metric thread
mounting bolts through the Holding Fixture and
thread them finger-tight on both sides into the
compressor cylinder until the step of the fixture
protrusions contact the compressor Shell. Check
to be sure the step protrusions do not overlap the
cylinder but will pass both sides. Allow
compressor to cool to room temperature before
removing compressor shell.
2-J-25008 -A
HOLDING FIXTURE
Fig. 48 Releasing Shell Retaining Strap
HOLDING FIXTURE
2-SHELL TO
CYLINDER
O-RING
3-ALTERNATELY
TIGHTEN
SCREWS
APPROX.
114 TURN
4-STEP CONTACTS
COMPRESSOR
SHELL
Fig. 49 Removing Shell
7. Alternately tighten each bolt approximately 1/4
turn to push the Shell free of the O-rings on the
cylinder.
If one screw appears to require more force to turn
than the other, immediately turn the other screw
to bring the screw threading sequence in-step or
the Shell will be cocked and made more difficult
to remove. Normal removal does not require
much force on the wrench if the screws are kept
in-step while turning. The Shell can be removed
by hand as soon as the Shell is free of the shell to
cylinder O-rings. Do not turn the screws any
further than necessary to release the Shell.
8. Remove the compressor Shell and remove the
Holding Fixture J-25008-A from the compressor.
Reverse the Holding Fixture to again hold the
compressor by the opposite side, using the
short-length screws with metric threads.
9. Remove and discard both cylinder to Shell
O-rings.

ENGINE GENERAL INFORMATION 6-3
B, Section 6E2 - Fuel Injection (TBI)
B, Section 6E3 - Fuel Injection (Ported)
ENGINE MECHANICAL DIAGNOSIS
The following diagnostic information covers common problems and possible causes. When
the proper diagnosis is made, the problem should be corrected by adjustment, repair or part
replacement as required. Refer to the appropriate section of the manual for these procedures.
EXCESSIVE OIL LOSS
B, External oil leaks. Tighten bolts and/or replace o Continuous high speed driving, and/or severe
gaskets and seals as necessary. usage
such as trailer hauling, will normally cause
decreased oil mileage.
e Improper reading of dipstick. Check oil with car PCV system malfunctioning. on a level surface and allow adequate drain-down Valve guides and/or valve stem seals worn, or time.
seals omitted. Ream guides and install oversize
service valves and/or new valve stem seals.
Improper Use S.A'E' Piston rings broken, worn, or not seateded. Allow viscosity for prevailing temperatures. See
adequate time for rings to seat. Replace broken
Owner's Manual for proper specifications.
or worn rings, as necessary.
Piston improperly installed or misfitted.
LOW OIL PRESSURE
Slow idle speed. Set idle speed to correct
specification, if not ECM controlled.
Incorrect, or malfunctioning, oil pressure switch.
Incorrect, or malfunctioning, oil pressure gage.
Replace with proper gage.
.*
Improper oil viscosity, or diluted oil. install oil of
proper viscosity for expected temperature, or
install new oil if diluted with moisture or
unburned fuel mixtures.
o Oil pump worn or dirty.
e Plugged oil filter.
e Oil pickup screen loose or plugged.
B, Hole in oil pickup tube.
e Excessive bearing clearance. Replace if necessary.
o Cracked, porous or plugged oil galleys. Repair or
replace block.
o Galley plugs missing or misinstalled. Install
plugs, or repair as necessary.
VALVE TRAIN NOISE
e Low oil pressure. Repair as necessary. (See o Broken valve spring.
preceding diagnosis for low oil pressure.)
o Sticking valves.
o Loose rocker arm attachments. Inspect and B, Lifters worn, dirty, or defective. Clean, inspect,
test and replace as necessary.
repair as necessary.
o Camshaft worn, or poor machining. Replace
o Worn rocker arm and/or pushrod. camshaft.
B, Worn valve guides.
ENGINE KNOCK DIAGNOSIS
KNOCKS COLD AND CONTINUES FOR TWO TO THREE MINUTES
INCREASES
WITH TORQUE
o Vacuum operated EFE engines may have valve o Excessive piston to bore clearance. Replace
knock. Replace EFE valve. piston.
e Flywheel contacting splash shield. Reposition
splash shield.
e Loose or broken balancer or drive pulleys.
Tighten, or replace as necessary. Cold engine piston knock usually
disappears when the cylinder is grounded
out. Cold engine piston knock which
disappears in 1.5 minutes should be
considered acceptable.