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Notice your HMMWV runs hot at 210-230F and saps the engine power when the fan engages? Upgrade your obsolete hydraulic fan setup with our modern thermostatic cooling kit.


The stock HMMWV system was designed to run HOT to efficiently burn multi-fuel and JP8 (jet fuel). While this is fine for a military vehicle that spends most of its life in storage with little mileage, its far from ideal from a longevity standpoint and is the cause for many heat related engine issues, specifically the block cracking near the #8 cyl.


Our bolt-on cooling upgrade kit includes our high-flow fan, severe duty clutch, adaptor (centering pin), and all required hardware (nuts, bolts and studs). This will allow removal of the factory fan, hydraulic clutch, solenoid control valve (cadillac valve), time delay module (TDM) and associated hydraulic hoses.


Key benefits:

  • Drops and maintains engine operating temperature between 185-190f for increased longevity
  • Significantly decreases engine noise 
  • Less fan cycling
  • Reduced HP draw on the engine when engaged 
  • Incredibly reliable with no hydraulic system/clutch to fail
  • Retains original water fording depth of 30"

Requires minor (simple) modification to existing waterpump pulley.


Designed for 6.2 and 6.5  engines with V-belt setups.



Model (Serial Number Range)

M966 (000001 to 099999)
M966A1 (100000 to 163XXX)
M996 (000001 to 099999)
M996A1 (100000 to 163XXX)
M998 (000001 to 099999)
M998A1 (100000 to 163XXX)
M1026 (000001 to 099999)
M1026A1 (100000 to 163XXX)
M1035 (000001 to 099999)
M1035A1 (100000 to 163XXX)
M1038 (000001 to 099999)
M1038A1 (100000 to 163XXX)
M1043 (000001 to 099999)
M1043A1 (100000 to 163XXX)
M1044 (000001 to 099999)
M1044A1 (100000 to 163XXX)
M1045 (000001 to 099999)
M1045A1 (100000 to 163XXX)
M1046 (000001 to 099999)
M1046A1 (100000 to 163XXX)
M1097 (000001 to 099999)
M1097A1 (100000 to 163XXX)
M1121 (100000 to 163XXX)

Heavy Duty Engine Cooling Kit (HMMWV V-Belts)

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