The Cooling System Regulates Engine Operating Tem - Jeep 1997 Grand Cherokee Service Manual

ZG
GENERAL INFORMATION
COOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . 1
RADIATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ENGINE ACCESSORY DRIVE BELTS . . . . . . . . . 2
COOLANT TANK . . . . . . . . . . . . . . . . . . . . . . . . 2
WATER PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . 3
COOLANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
LOW COOLANT LEVEL SENSOR
DESCRIPTION AND OPERATION
COOLANT PERFORMANCE . . . . . . . . . . . . . . . . 4
COOLING SYSTEM HOSES . . . . . . . . . . . . . . . . 5
VISCOUS FAN DRIVE . . . . . . . . . . . . . . . . . . . . 6
BELT TENSION . . . . . . . . . . . . . . . . . . . . . . . . . 6
AUTOMATIC BELT TENSIONER . . . . . . . . . . . . . 7
THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . 4
PRESSURE/VENT CAP . . . . . . . . . . . . . . . . . . . 4
DIAGNOSIS AND TESTING
PRELIMINARY CHECKS
THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . 13
VISCOUS FAN DRIVE
RADIATOR COOLANT FLOW CHECK
TESTING COOLING SYSTEM FOR LEAKS
LOW COOLANT LEVEL- AERATION . . . . . . . . . 15
BELT DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . 15
SERVICE PROCEDURES
COOLANT LEVEL CHECK . . . . . . . . . . . . . . . . 17
GENERAL INFORMATION
COOLING SYSTEM

The cooling system regulates engine operating tem-

perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible, maintains
normal operating temperature and prevents over-
heating.
The cooling system also provides a means of heat-
ing the passenger compartment. The cooling system
is pressurized and uses a centrifugal water pump to
circulate coolant throughout the system. A water
manifold collects coolant from the cylinder heads. A
separate and remotely mounted, pressurized coolant
tank using a pressure/vent cap is used.
COOLING SYSTEM COMPONENTS
The cooling system consists of:
• A brass-core radiator with plastic side tanks
• A radiator mounted fill vent valve
• A separate pressurized coolant tank
COOLING SYSTEM
CONTENTS
page
. . . . . . . . . . . 4
. . . . . . . . . . . . . . . . . . 7
. . . . . . . . . . . . . . . . . . . 13
. . . . . . . 13
. . . 14
DRAINING COOLING SYSTEM
REFILLING COOLING SYSTEM . . . . . . . . . . . . 17
COOLANT REPLACEMENT . . . . . . . . . . . . . . . 18
REMOVAL AND INSTALLATION
RADIATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
FAN BLADE REMOVAL
VISCOUS FAN DRIVE
THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . 21
DRIVE BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
AUTOMATIC BELT TENSIONER . . . . . . . . . . . . 22
WATER PUMP . . . . . . . . . . . . . . . . . . . . . . . . . 22
CLEANING AND INSPECTION
WATER PUMP . . . . . . . . . . . . . . . . . . . . . . . . . 24
RADIATOR CLEANING . . . . . . . . . . . . . . . . . . . 24
FAN BLADE . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
COOLING SYSTEM CLEANING/REVERSE
FLUSHING . . . . . . . . . . . . . . . . . . . . . . . . . . 25
ADJUSTMENTS
DRIVE BELT TENSION . . . . . . . . . . . . . . . . . . . 25
SPECIFICATIONS
COOLING SYSTEM CAPACITY
THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . 26
TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . 26
• A cam type pressure/vent cap mounted to the
coolant tank
• Cooling fan (mechanical)
• Thermal viscous fan drive
• Fan shroud
• Thermostat
• Coolant
• Low coolant level sensor
• Low coolant warning lamp
• Coolant temperature gauge
• Water pump
• Hoses and hose clamps
COOLANT ROUTING
For cooling system flow routing, refer to (Fig. 1)
RADIATOR
The radiator used with the 2.5L diesel is con-
structed of a horizontal cross-flow brass core with
plastic side tanks.
COOLING SYSTEM 7 - 1
page
. . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . 20
. . . . . . . . . . . . 26