JLG 4017RS Service Manual - Manual (Page 118)

Engine
7-4 3614RS, 4017RS
7.4 ENGINE COOLING SYSTEM
7.4.1 Surge Tank Cap
A 1 Bar (14.5 psi) cap is used on the surge tank. 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 up,
thermostat may be stuck in the open position and
requires replacement.
• If engine runs hot, check temperature of upper radi-
ator hose.
• If hose is not hot, thermostat may be stuck in 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 boom, lower boom, place transmission in (N)
NEUTRAL, engage parking brake, and shut engine OFF.
2. Place a Do Not Operate Tag on both ignition key switch
and steering wheel.
3. Open engine cover. Allow system fluids to cool.
4. Properly disconnect battery.
5. Slowly turn surge tank cap to 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 container. Loosen the drain plug and slowly
remove to allow coolant to drain. Transfer coolant into a
properly labeled container. Dispose of properly if
coolant needs to be replaced. Replace the radiator drain
plug.
7. Remove capscrews securing thermostat housing (1) to
engine.
8. Remove thermostat housing, old gasket and
thermostat. Clean all gasket surfaces. DO NOT let any
debris into thermostat opening.
Note: ALWAYS use correct thermostat and install a new gasket.
NEVER operate engine without a thermostat, or engine
damage will result.
b. Thermostat Installation
1. Install engine thermostat, thermostat gasket and
thermostat housing. Secure with the previously
removed capscrews.
2. Properly connect battery.
3. Open 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
radiator cap. Add coolant to surge tank until 1/4 to 1/2
full. This overfilling will compensate for any air trapped
in 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 engine cover.
6. Remove Do Not Operate Tags from both ignition key
switch and steering wheel.
M 7410 Z
1