Inhibitors; Testing Coolant; Thermostat Remove And Replace; Water Pump-6 Cylinder - Pontiac Grand Prix Service Manual

ENGINE COOLING AND LUBRICATION 6A-3
5. Drain sufficient water to allow addition of proper
quantity of coolant.
Do not overfill. Coolant should be 1" below filler neck
opening with hot engine, 3 " below filler neck with cold
engine for all models.
CAUTION: A pressure radiator cap is used to provide
the best cooling. When removing, rotate cap to leji very
slowly.
If
hissing noise is heard stop and allow pressure
to decrease before removing cap completely.
To assure most effective heater performance, all
models are equipped with a 190°F. thermostat. There-
fore, the use of Pontiac-approved inhibited glycol-type
engine coolant gives best heater performance.
Non-glycol'base coolant should not be used.
INHIBITORS
When only water is in the system, a cooling system
corrosion inhibitor must be used.
TESTING COOLANT
In using a hydrometer to determine the freezing point
of radiator solution, make sure correct hydrometer
markings are read. Unless hydrometer is provided with
means for temperature correction, test should be made
at temperature at which hydrometer is calibrated, for if
the solution is warmer or colder large errors may result
(in some cases as much as 30°F). Most good hydrome-
ters are equipped with a thermometer and temperature
correction scale which allows an accurate test of
freezing point over a range of temperatures.
THERMOSTAT-REMOVE AND REPLACE
1. Drain radiator level to below thermostat and
remove water outlet assembly from rocker arm cover
(6 cyl.), intake manifold (8 71.).
2. Remove thermostat. Unless obviously defective, test
thermostat as follows before replacing with new one:
a.
Immerse unit and thermometer in container of
water over a heater. While heating water do not rest
either thermometer or thermostat on bottom of
container as this will cause them to be at higher
temperature than the water.
b. Agitate water to insure uniform temperature of
water, thermostat and thermometer.
A new thermostat (190") valve should start to open
(.002") at a temperature of 187OF. to 1930F., and
should be fully open (3/8") or more at a temperature
not in excess of 222°F. A used thermostat can be about
7°F.
above or below this setting (2830
-
197.) without
adverse effect and should not be replaced. If thermo-
stat does not operate at specified temperatures, . i t
should be replaced as it cannot be adjusted.
3. Install thermostat with pellet or cartridge projecting
down into water passage.
4. Using new gasket, install water outlet fitting.
Tighten bolts to 21 lb. ft. (6 cyl.), 28 Ib. fi. (8 cyl).
5. Refill radiator to approximately 3" below fffler neck
for all models.
WATER PUMP-8 CY I-INDER
NOTE: Waterpump is serviced only as an assembly.
1. Drain radiator.
2. Loosen generator at adjusting strap and remove fan
belt from fan pulley.
3. Remove fan and pulley.
4. Remove water pump retaining bolts and remove
Pump.
5. Install pump by reversing above steps. Rghten
water pump attaching bolts to 15 lb. ft. torque. Adjust
belt for proper tension on chart at end of this section.
WATER P U M P 4 CYLINDER
REMOVE
1. Drain cooling system and remove water inlet and
heater hoses.
2. Remove all fan and accessory drive belts.
3. Remove fan and pump pulley.
4. Remove upper front timing belt cover.
5. Remove two front bolts attaching accessory drive
ho&g to block.
6. Remove water pump to cylinder block attaching
nuts and bolts and remove pump from engine.
REPLACE
1. Install pump and attaching nuts and bolts. Tighten
to 20 lb. ft. torque.
2. Replace cover and two front accessory drive
attaching bolts. Tighten bolts to 15 lb. fi. torque.
3. Replace timing belt cover.
4. Replace fan and pump pulley.
5. Install all fan and accessory drive belts.