Pontiac Fiero 1988 Service Manual page 356

ENGINE COOLING 6B-7
PROBLEMS NOT R E Q U I R I N G D I S A S S E M B L Y OF COOLING S Y S T E M -
1. LARGE OBSTRUCTIONS BLOCKING RADIATOR OR CONDENSER
a. A U X I L I A R Y O I L C O O L E R S " !
b. L I C E N S E P L A T E S | — R E L O C A T E
c. S P A R E T I R E S J
d. I C E , MUD OR SNOW OBSTRUCTING GRILLE - REMOVE
2. ENGINE OIL O V E R F I L L - CHECK ENGINE OIL DIPSTICK
3. WRONG RADIATOR FOR APPLICATION - CHECK PART NO. AGAINST PARTS LIST
4. LOOSE, DAMAGED OR MISSING AIR SEALS - SEE BODY SERVICE MANUAL
5. MISSING OR DAMAGED LOWER AIR BAFFLE - SEE BODY SERVICE MANUAL
6. WRONG IGNITION TIMING - SEE CHASSIS SERVICE MANUAL
PROBLEMS REQUIRING D I S A S S E M B L Y OF COOLING SYSTEM -
1. INCORRECT OR DAMAGED FAN - CHECK PART NO. AGAINST PARTS LIST
2. FAULTY EMISSION SYSTEM COMPONENTS (COULD CAUSE OVERHEATING AT IDLE)
a. PCV VALVE '
b. TVS OR TCS_
3. PRESSURE CHECK COOLING SYSTEM WITH PRESSURE CAP INSTALLED - WILL SHOW
IF PRESSURE CAP LEAKS BECAUSE OF RADIATOR FILLER NECK DAMAGE
4. DEFECTIVE WATER PUMP
a. ERODED OR BROKEN IMPELLER VANES
b. FAILED BEARING OR SEAL - CHECK FOR SHAFT OR BEARING PLAY
5. PLUGGED RADIATOR TUBES - SEND TO RADIATOR REPAIR SHOP FOR FLOW CHECK
6. INTERNAL SYSTEM LEAKS
a. HEAD GASKET - SEE CHASSIS SERVICE MANUAL
b. CRACKED BLOCK
c. TIMING CHAIN COVER
d. INTAKE MANIFOLD GASKET
7. PLUGGED COOLANT PASSAGES IN CYLINDER HEADS - REMOVE HEADS AND CHECK VISUALLY
SEE CHASSIS SERVICE MANUAL
520010 6B
Figure 6 Cooling System Diagnosis Chart (3 of 3)
ENGINE OVERHEAT - BOILING - POOR ENGINE COOLING
1. RELIEVE PRESSURE AND CAREFULLY REMOVE RADIATOR CAP.
2. RUB 20C°F. TEMPERATURE STICK* ONTO THERMOSTAT HOUSING.
3. WARM UP ENGINE AT FAST IDLE!
WATCH FOR COOLANT FLOW BEFORE MARK BEGINS TO MELT.
NO COOLANT FLOWl
COOLANT FLOW
PROBLEM IS CAUSED BY
OTHER THAN BAD THERMOSTAT.
COLD ENGINE - SLOW WARMUP - NOT ENOUGH HEAT
1. RELIEVE PRESSURE ANO CAREFULLY REMOVE RADIATOR CAP.
2. RUB 18S°F. TEMPERATURE STICK* ONTO THERMOSTAT HOUSING.
3. WARM UP ENGINE AT FAST IDLE.
WATCH FOR COOLANT FLOW BEFORE MARK BEGINS TO MELT.
COOLANT FLOWa
NO COOLANT FLOW
PROBLEM IS CAUSED BY
OTHER THAN BAD THERMOSTAT.
•NOTE: THE TEMPERATURE STICK IS A PENCIL LIKE DEVICE WHICH HAS A WAX MATERIAL CONTAINING CERTAIN CHEMICALS WHICH MELT AT A
GIVEN TEMPERATURE. THEMPERATURE STICKS CAN BE USED TO DETERMINE A THERMOSTAT'S OPERATING TEMPERATURE BY RUBBING 188°F. AND
206 F. STICKS ON THE THERMOSTAT HOUSING. THE MARKS MADE BY THE STICKS SHOULD MELT WHEN COOLANT TEMPERATURES OF 188°F. AND
206 F. ARE REACHEO. RESPECTIVELY. THESE TEMPERATURES ARE THE NORMAL OPERATING RANGE OF THE THERMOSTAT. THEREFORE. IF THE
COOLANT FLOWS AS INDICATED ON THE DIAGNOSIS CHART. THE THERMOSTAT MAY BE DEFECTIVE.
520011-6B
Figure 7 Thermostat Diagnosis Chart