ENGINE
TABLE OF CONTENTS
page page
ENGINE
OPERATION ............................6
DIAGNOSIS AND TESTING
COOLING SYSTEM .....................6
COOLING SYSTEM LEAK TEST ..........10
COOLING SYSTEM AERATION ...........11
COOLING SYSTEM DEAERATION .........11
STANDARD PROCEDURE
ROUTINE COOLANT LEVEL CHECK .......11
ADDING ADDITIONAL COOLANT .........12
DRAINING COOLING SYSTEM ...........13
FILLING COOLING SYSTEM .............13
CLEANING ............................14
COOLANT
DESCRIPTION - ENGINE COOLANT .........15
DIAGNOSIS AND TESTING - COOLANT
CONCENTRATION TESTING .............15
STANDARD PROCEDURE - COOLANT
SERVICE ............................16
PRESSURE CAP
DESCRIPTION .........................16
OPERATION ...........................16
DIAGNOSIS AND TESTING - COOLING
SYSTEM PRESSURE CAP TESTING .......16
INSPECTION ..........................16
COOLANT PRESSURE BOTTLE
OPERATION ...........................17
REMOVAL .............................17
INSTALLATION .........................17
ENGINE COOLANT TEMPERATURE SENSOR
DESCRIPTION .........................18
OPERATION ...........................18
REMOVAL .............................18
INSTALLATION .........................18
ENGINE COOLANT THERMOSTAT
DESCRIPTION .........................18
OPERATION ...........................18
DIAGNOSIS AND TESTING - THERMOSTAT . . . 18
REMOVAL .............................19
INSTALLATION .........................19
HOSE CLAMPS
DESCRIPTION .........................20
COOLING SYSTEM HOSES
DESCRIPTION .........................20
RADIATOR FAN
DESCRIPTION .........................20
OPERATION ...........................21
REMOVAL .............................22
INSTALLATION .........................23
RADIATOR
REMOVAL .............................24
INSTALLATION .........................25
WATER PUMP
REMOVAL .............................25
INSPECTION ..........................25
INSTALLATION .........................26
ENGINE
OPERATION
The cooling systems maintains engine temperature
in a range that will provide satisfactory engine per-
formance and emission levels under all expected driv-
ing conditions.
It also provides a source of hot water (coolant) for
heater performance. It performs this task by trans-
ferring heat from engine block to the coolant, then
moving this heated coolant to the radiator where the
heat is transferred to the ambient air.
• When engine is cold the thermostat is closed.
The cooling system has no flow through the radiator.
The coolant flows through the engine, water pump,
and heater.
• When engine is warm the thermostat is full
open. The coolant flows through the radiator, heater,
and water pump.
DIAGNOSIS AND TESTING
COOLING SYSTEM
Establish what driving condition caused the cooling
system complaint. The problem may be caused by an
abnormal load on the system such as the following:
prolonged idle, very high ambient temperature, slight
tail wind at idle, slow traffic speed, traffic jam, high
speed, steep grade.
VISUAL INSPECTION
If the cooling system problem is not caused by a
driving condition, perform a visual inspection to
determine if there was a recent service or accident
repair, including the following:
• Loose/damaged accessory drive belt
• Incorrect cooling system refilling (trapped air or
low level)
• Brakes possibly dragging
7 - 6 ENGINE ZB
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