QuestionHow do I change the thermostat on this vehicle?
AnswerTHERMOSTAT - 5.2L/5.9L ENGINES
REMOVAL
WARNING: DO NOT LOOSEN RADIATOR DRAINCOCK WITH SYSTEM HOT AND PRESSURIZED. SERIOUS BURNS FROM COOLANT CAN OCCUR.
Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
If thermostat is being replaced, be sure that replacement is specified thermostat for vehicle model and engine type.
Factory installed thermostat housings on 5.2/5.9L engines are installed on a gasket with an anti-stick coating. This will aid in gasket removal and clean-up.
Disconnect negative battery cable at battery.
Drain cooling system until coolant level is below thermostat. Refer to Draining Cooling System in this group.
Air Conditioned vehicles: Remove support bracket (generator mounting bracket-to-intake manifold) located near rear of generator Generator Support Bracket - 5.2L/5.9L Engines .
On air conditioning equipped vehicles, the generator must be partially removed.
Remove generator drive belt as follows: Drive belts on the 5.2L/5.9L engines are equipped with a spring loaded automatic belt tensioner Automatic Belt Tensioner - 5.2L/5.9L Engines
Attach a socket/wrench to pulley mounting bolt of automatic belt tensioner Automatic Belt Tensioner - 5.2L/5.9L Engines
Rotate tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
Remove belt from vehicle.
Remove two generator mounting bolts. Do not remove any wiring at generator. If equipped with 4WD, unplug 4WD indicator lamp wiring harness (located near rear of generator)
Remove generator. Position generator to gain access for thermostat gasket removal.
Remove upper radiator hose clamp Hose Clamp Tool - Typical and upper radiator hose at thermostat housing.
Position wiring harness (behind thermostat housing) to gain access to thermostat housing.
Remove thermostat housing mounting bolts, thermostat housing, gasket and thermostat Thermostat - 5.2L/5.9L Engines Discard old gasket.
INSTALLATION
Clean mating areas of intake manifold and thermostat housing.
Install thermostat (spring side down) into recessed machined groove on intake manifold Thermostat - 5.2L/5.9L Engines
Install gasket on intake manifold and over thermostat Thermostat - 5.2L/5.9L Engines
Position thermostat housing to intake manifold. Note the word FRONT stamped on housing Thermostat Position - 5.2L/5.9L Engines For adequate clearance, this must be placed towards front of vehicle. The housing is slightly angled forward after installation to intake manifold.
Install two housing-to-intake manifold bolts. Tighten bolts to 23 N·m (200 in. lbs.) torque
CAUTION: Housing must be tightened evenly and thermostat must be centered into recessed groove in intake manifold. If not, it may result in a cracked housing, damaged intake manifold threads or coolant leak.
Install upper radiator hose to thermostat housing.
Air Conditioned vehicles:
CAUTION: When installing the serpentine accessory drive belt, belt must be routed correctly. If not, engine may overheat due to water pump rotating in wrong direction. Refer to Belt Routing - 5.2L/5.9L Engines for correct 5.2/5.9L engine belt routing. Or, refer to the Belt Routing Label located in the engine compartment. The correct belt with correct length must be used.
Install generator. Tighten bolts to 41 N·m (30 ft. lbs.) torque.
Install support bracket (generator mounting bracket-to-intake manifold) Generator Support Bracket - 5.2L/5.9L Engines Tighten bolts to 54 N·m (40 ft. lbs.) torque.
Position drive belt over all pulleys except idler pulley (located between generator and A/C compressor)
Attach a socket/wrench to pulley mounting bolt of automatic belt tensioner Automatic Belt Tensioner - 5.2L/5.9L Engines
Rotate socket/wrench clockwise. Place belt over idler pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated on all pulleys.
Fill cooling system. Refer to Refilling Cooling System in this group
Connect negative battery cable to battery.
Start and warm the engine. Check for leaks
