Questions & Answers
Questions: 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?
Question By: Kevin Hobert on May 29 2021 9:13 PM
160 is what most people go with. It warms your engine up faster to operating temps.
Answer By: Willys Jeep Parts Tech on Jun 1 2021 5:50 AM
Questions: 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
Question By: Gavin Harrison on Oct 29 2014 12:00 AM
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.
Answer By: Willys Tech on Oct 29 2014 12:00 AM