Engine
7-5
6036, 6042, 8042, 10042, 10054 31211015
7.4 ENGINE COOLING SYSTEM
7.4.1 Coolant System Pressure Cap
The surge tank cap is designed to use a 17 psi (120 kPa) cap.
An incorrect or malfunctioning cap can result in the loss of
coolant and a hot-running engine.
7.4.2 Thermostat Replacement
Before considering thermostat replacement, check the
coolant level, fan belt tension and instrument cluster
temperature indicator.
• If engine seems to take a long time to warm, thermostat
may be stuck in the open position and requires
replacement.
• If engine runs hot, check the temperature of the upper
radiator hose.
• If hose is not hot, thermostat may be stuck in the closed
position.
• If engine has overheated, performance may
suffer, indicating other damage including a leaking
cylinder head gasket, cracked cylinder head or block,
and/or other internal engine damage.
a. Thermostat Removal
1. Park machine on a firm, level surface, level machine, fully
retract the boom, lower boom, place transmission in (N)
NEUTRAL, engage parking brake, and shut engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and steering wheel, stating that the machine
should not be operated.
3. Open the engine cover. Allow the system fluids to cool.
4. Properly disconnect the battery(s). Refer Section 9.8,
“Battery”, for procedure.
5. Slowly turn the surge tank cap to the first stop and allow
any pressure to escape. Remove surge tank cap.
6. Place a funnel at base of radiator to channel drained
coolant into a container. Loosen drain petcock and
slowly allow coolant to drain. Transfer coolant into a
properly labeled container. Dispose of properly if
coolant needs to be replaced. Tighten the radiator drain
petcock.
7. Loosen upper radiator hose clamp and remove the
radiator hose from the thermostat housing.
8. Remove four bolts securing thermostat housing (1) to
the engine.
9. Remove thermostat housing, old gasket and
thermostat. Clean all gasket surfaces. DO NOT allow dirt
or debris into the thermostat opening.
Note: ALWAYS use correct thermostat and new gasket. NEVER
operate engine without a thermostat.
b. Thermostat Installation
1. Install engine thermostat, gasket and housing. Secure
with previously removed bolts. Torque as required.
2. Properly connect the battery. Refer Section 9.8,
“Battery”, for procedure.
3. Open the surge tank cap and fill the radiator completely
with a 50/50 mixture of ethylene glycol and water. Add
coolant solution at a maximum rate of 1.3 gallons per
minute (5 liters per minute). Replace and tighten surge
tank cap. Add coolant to surge tank until 1/4 to 1/2 full.
This overfilling will compensate for any air trapped in
the cooling system.
4. Run engine to operating temperature. Visually check for
leaks with engine running. Check coolant level in surge
tank and fill, or drain, as necessary.
5. Close and secure the engine cover.
6. Remove the Do Not Operate Tags from both the ignition
key switch and the steering wheel.
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