Pontiac Fiero 1988 Service Manual page 350

ENGINE COOUNG 6B-1
SECTION 6B
ENGINE COOLING
CONTENTS
G e n e r a l D e s c r i p t i o n
6B-1
Radiator 6B-1
Radiator Cap . . . . . . 6B-1
Recovery bottle 6B-2
Fan 6B-2
Temperature Switch 6B-3
Coolant Temperature Fan Switch 6B-3
T h e r m o s t a t . . . . . . . . . . . . . . . . 6B-3
Coolant Recovery System 6B-3
D i a g n o s i s
6B-3
S e r v i c e P r o c e d u r e s
6B-3
Cooling System Care 6B-3
Draining and Refilling the Cooling System . . . 6B-4
Drive Belts 6B-8
A l u m i n u m R a d i a t o r R e p a i r
6B-8
D i a g n o s i s
. . . . . . . . . 6B-9
Leak Testing . . . . 6B-9
On-Vehicle Pressure Testing . . . . . . . . . . . . . . 6B-10
Off-Vehicle Leak Testing 6B-10
Repairable Leaks 6B-10
Repair Methods 6B-11
Cooling Fin Removal 6B-11
Tube Blocking 6B-11
Header Repair 6B-11
General Core Repair 6B-12
Tank Gasket Leak Repair 6B-13
Oil Cooler Gasket Replacement 6B-14
Recore 6B-14
On-Vehicle S e r v i c e 6B-15
Thermostat (2.5L)
6B-15
Thermostat (2.8) 6B-15
Electric Cooling Fan 6B-15
Water Pump (2.5L) 6B-16
Water Pump (2.8L) 6B-16
Coolant Recovery Bottle 6B-17
Radiator 6B-17
Belt Tension.. 6B-17
GENERAL DESCRIPTION
The cooling system maintains engine tempera-
ture at an efficient level during all engine operating
conditions. When the engine is cold the system cools
slowly, or not at all, to allow the engine to warm up
quickly.
The cooling system includes a radiator and
recovery sub-system, cooling fan, thermostat and
housing, water pump, and drive belt(s).
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 defrost-
ing. 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 trans-
mission fluid circulation. Cars with manual transmis-
sions 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
5" below the filler neck which reads, "Important —
for repair see Harrison Service Manual". Service pro-
cedures for the aluminum plastic radiator are
described in that manual and in this section.
Radiator C a p
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.