Radiator; Water Pump Bypass Hose-5.2/5.9L; Engines; Description And Operation - Jeep 1997 Grand Cherokee Service Manual

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GENERAL INFORMATION (Continued)
WATER PUMP BYPASS HOSE—5.2/5.9L V-8

ENGINES

A water pump bypass hose (Fig. 3) is used between
the intake manifold and water pump on all 5.2/5.9L
V-8 engines.
Fig. 3 Water Pump Bypass Hose—5.2/5.9LEngines
COOLANT
The cooling system is designed around the coolant.
Coolant flows through the engine water jackets
absorbing heat produced during engine operation.
The coolant carries heat to the radiator and heater
core. Here it is transferred to ambient air passing
through the radiator and heater core fins. The cool-
ant also removes heat from the automatic transmis-
sion fluid in vehicles equipped with an automatic
transmission.

RADIATOR

All vehicles are equipped with a cross flow type
radiator with plastic side tanks.
Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.

DESCRIPTION AND OPERATION

AUTOMATIC TRANSMISSION OIL COOLERS

There are three types of automatic transmission oil
coolers:
• An oil-to-coolant type. This is supplied as stan-
dard equipment on vehicles with an automatic trans-
mission. It is mounted in the radiator outlet tank.
SHAFT CRANKSHAFT WATER PUMP
WATER
PUMP PUL-
LEY
BYPASS PULLEY HOSE COOLANT OVERFLOW HOSE
• An external auxiliary oil-to-air cooler. This is
supplied as optional equipment. It is mounted in
front of the radiator and air conditioning condenser
and behind the grille.
• An internal high capacity/high efficiency cooler.
This cooler is also an oil-to-coolant type which con-
sists of plates mounted in the radiator outlet tank
and is also supplied as optional equipment.
NOTE: IF A VEHICLE WITH THE TRAILER TOWING
OPTION DOES NOT HAVE AN EXTERNAL AUXIL-
IARY TRANSMISSION
EQUIPPED WITH THE INTERNAL, HIGH-EFFICIENCY
COOLER.

COOLANT RESERVE/OVERFLOW SYSTEM

This system works along with the radiator pres-
sure cap. This is done by using thermal expansion
and contraction of the coolant to keep the coolant
free of trapped air. It provides:
• A volume for coolant expansion and contraction.
• A convenient and safe method for checking/ad-
justing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
• Some reserve coolant to the radiator to cover
minor leaks and evaporation or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
The coolant reserve/overflow system has a radiator
mounted pressurized cap, an overflow tube and a
plastic coolant reserve/overflow tank (Fig. 4) mounted
to the right inner fender.
Fig. 4 Coolant Reserve/Overflow Tank—Typical
COOLANT RESERVE/OVER- COOLANT LEVEL SENSOR FLOW TANK
COOLING SYSTEM
COOLER, THAN IT
7 - 3
IS