Water Plimp-6 Cylinder; Flushing Cooling System; Preparing Cooling System For Coolant; Checking And Filling Cooling System - Pontiac Grand Prix Service Manual

6A-2 1969
PONTlAC SERVICE MANUAL
housing and aluminum timing chain cover are all part
of the coolant circulation system.
The water pump impeller turns on a steel shaft
mounted on a double row of permanently lubricated,
sealed ball bearings. A bellows-type seal is seated in
the water pump body between bearing and impeller.
The seal surface is a phenolic washer which is held by
the spring-loaded bellows against a ceramic seal seat
which seals the pump shaft via a rubber boot.
The water pump on 1969 V-8 engines has been
redesigned by positioning the bearing forward to
provide improved b e a ~ g loads and better durability.
The inlet side of the pump is connected to the lower
radiator tank by means of a hose. A water leg in
intake manifold connects to the timing chain cover to
provide recirculation of water when the thermostat is
closed. The timing chain cover also has a heater water
return connection.
WATER PLIMP-6 CYLINDER
The centrifugal-type water pump contains an impeller
which turns on a steel shaft which rotates in a ball
bearing. A bellows-type seal is seated in the water
pump body between the bearing and impeller.
The inlet side of the pump is connected
to
the right
radiator tank by a hose. Above the pump inlet from
the radiator is the inlet from the heater core. Coolant
passages in the block and water pump index with each
other to permit a completely full flow coolant internal
recirculation system. This provides a more positive
engine temperature regulation.
FAN
The fan is used to increase the air flow through the
radiator at all speeds.
All cars except F i b i r d 400, G.T.O., 428 H.O. and
air
conditioned cars have a fan which has four blades
which are unevenly spaced and have curled tips
to
provide minimum noise. Cars equipped with the Ram
Air IV
option use a special four bladed fan. See fan
usage specifications for proper application of power
flex and thermo clutch fans.
A fan shroud is used on all V-8 equipped cars. This
greatly assists the cooling characteristics by preventing
the recirculation of air around the fan.
SERVICE OPERATIONS
CHECKING AND FILLING COOLING SYSTEM
The cooling system requires little care except for
maintaining an adequate coolant level. If GM gly-
col-type inhibited engine coolant is used, it is not
necessary to drain the coolant for summer driving
because this coolant has been especially formulated to
last 24 months in the cooling system. After service for
24 months, drain the system, flush it with water, and
refill with an inhibited year-round coolant meeting the
GM 1899M specification. If other than Pontiac-ap-
proved inhibited glycol-type antifreeze solution is used,
the cooling system should be drained, flushed and
refilled for the summer months. When water is used, a
good corrosion inhibitor must be added to the system.
Failure to use an inhibited coolant may result in severe
corrosion damage to the cooling system components.
FLUSHING COOLING SYSTEM
I. Drain radiator and block by opening drain plug on
,
radiator left tank and removing plug on left side of 6
. ,
cylinder engine block and on both sides of 8 cylinder
engine block.
2. After system is empty, with drains open, run water
into radiator. Engine should be running and occasion-
ally accelerated to aid in circulating water and
dislodge rust and scale.
CAUTION: Do not introduce cold water into a hot
engine or block may be cracked. Allow engine to cool,
then add water with engine running.
3. Where there is difficulty in getting water to run clear
or there is
an
excessive amount of rust and scale, the
cooling system should be cleaned with a cleanser
(reputable source) supplied for that purpose. If force
flushing equipment is used, it should be used on the
radiator only (engine to radiator inlet and outlet hoses
removed) as any reverse flushing of the block with the
water pump in place may cause the water pump seal to
leak, if flushing pressure is excessive.
PREPARING COOLING SYSTEM FOR COOLANT
The cooling system should be properly prepared for
the addition of coolant every two years.
To properly prepare cooling system:
1. Bring engine up to operating temperature.
2. Flush out cooling system as indicated previously.
3. Tighten all hose connections on radiator, engine,
heater and defroster. Replace any deteriorated hose.
Check to see that radiator hold-down bolts are
tightened properly.
4. Fill system with water and operate engine, checking
for water leaks at radiator core, hose connections,
water pump seal and gaskets, heater and defroster
connections, and head to block joint.