GENERAL INFORMATION
COOLING SYSTEM
The cooling system consists of an engine cooling
module, thermostat, coolant, a water pump to circu-
late the coolant. The engine cooling module may con-
sist of a radiator, electric fan motor, shroud, radiator
pressure cap, coolant reserve system, transmission
oil cooler and lines, hoses, clamps, and air condition-
ing condenser.
• When Engine is cold: Thermostat is closed, cool-
ing system has no flow through the radiator. The
coolant bypass flows through the engine and heater
core.
• When Engine is warm: Thermostat is open, cool-
ing system has bypass flow and coolant flow through
radiator and heater core.
The primary purpose of a cooling system is to
maintain engine temperature in a range that will
provide satisfactory engine performance and emission
levels under all expected driving conditions. It also
provides hot water (coolant) for heater performance
and cooling for automatic transmission oil. It does
this by transferring heat from engine metal to cool-
ant, moving this heated coolant to the radiator, and
then transferring this heat to the ambient air.
Coolant flow circuits for 2.0L and 2.4L engine
equipped vehicles are shown in (Fig. 1). The 2.5L
engine coolant flow circuit is shown in (Fig. 2).
WATER PIPES—2.5L
The 2.5L engine use metal piping beyond the lower
radiator hose to route coolant to the suction side of
water pump, located in the V of the cylinder banks.
The pipes are also provided with inlet nipples for
thermostat bypass, heater return coolant hoses, and
brackets for rigid engine attachment. The pipes
employ O-rings for sealing at their interconnection
and to the water pump (Fig. 3).
ACCESSORY DRIVE BELTS
The engines are equipped with 2 accessory drive
belts. One belt drives the power steering pump, the
other drives the generator and air conditioning (Fig.
4) or (Fig. 5).
COOLANT RECOVERY SYSTEM (CRS)
This system works in conjunction with the pres-
sure cap to utilize thermal expansion and contraction
of the coolant to keep the coolant free of trapped air.
It provides a volume for expansion and contraction,
provides a convenient and safe method for checking
coolant level, and adjusting level at atmospheric
pressure without removing the pressure cap. It also
provides some reserve coolant to cover minor leaks
and evaporation or boiling losses. All vehicles are
equipped with this system (Fig. 6).
See Coolant Level Check Service, Deaeration and
Pressure Cap sections for operation and service.
Fig. 1 Cooling System Operation—2.0L and 2.4L Engines
7 - 2 COOLING SYSTEM JA
To Next Page
Loading...
