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Thermostat Assembly 180 degrees
Fits 41-71 Jeep & Willys

Part # 905594

New Replacement Thermostat in 180 degrees.

Recommended for all early vehicles in northern, very cold climates.

4-134 engine
6-161 engine
6-226 engine

41-45 MB
41-45 GPW
46-49 CJ-2A
49-53 CJ-3A
53-64 CJ-3B
55-71 CJ-5
50-52 M38
52-66 M38A1
46-64 Truck
46-64 Station Wagon
48-51 Jeepster

Part # Price





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I have a 1959 Willys CJ5 with the hurricane engine. I replaced the thermostat housing and gasket and the upper radiator hose. The Jeep didn’t have a thermostat when I did the replacement. Do I need a thermostat? Which one (180 or 160 degree). Do I need anything else to install the thermostat?

Willys Jeep Parts Tech:
160 is what most people go with. It warms your engine up faster to operating temps.

Is a thermostat housing retainer required to hold thermostat in place? I have a 55 CJ3b and had purchased a thermostat from O'Reilys and it does not open inside the jeep however when I boil it, it opens just fine. I am curious why I am having cooling issues. When I remove the thermostat entirely the jeep stays nice and cool. Winter is near and I want to use the heater and a thermostat is going to be needed to maintain optimum warmth from the engine coolant. Any suggestions? Thanks

Willys Tech:
On the 4-134 L head engines yes you need part number: 639651 to make work. On the 4-134 F head it is not required. They changed the design of the housing. O'Reillys probably sold you the wrong one. The ones we sell are proper.
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