Radiator Cap (4 Pound Bottom Mount) For 41-71 Jeep & Willys with 4-134 Engine
Replacement 4 pound cap. Ensures proper cooling for your Willys and Jeep vehicle restorations. For bottom mount Radiators.
Call Mike@Kaiserwillys.com for details at TOLL FREE 1-888-648-4923 (Mon-Fri, 9AM-5PM EST).
New Radiator Cap – Part#: 810391
Q: The title of the Jeep I’m working on says 1942, but it has a tail gate. I think those came later. The cap that is on it at the moment is round and is 2 – 7/8″ in total diameter. The neck coming up to it is about 1 – 5/8″ at the smallest inside measurement. The cap fits kind of tight, but I think it’s not the right one anyway, and since the bottom gasket is missing, we need a new one. Where do you measure to get the 2-7/8″ or the 3/4″ neck measurement?
- A: It’s probably a CJ-2A. You measure the inside of the cap or the ID of the neck.
- A: This is the correct one part number: 810391
Q: Which cap fits your radiator #908028 for the 1961 CJ-5?
- A: This is the proper one for you.
Q: Is this the correct cap for radiator PN# 640146?
- A: This should be the correct one for you.
Q: My title shows that I have 1946 Jeep. I am presently looking for a radiator cap for this Jeep. My current radiator cap measures 1-7/8″ on the inside diameter of the cap. It looks like the original cap. What cap do I need to get?
- A: This should be the proper one for you if you are bottom mount original radiator.
Q: I have added a coolant recovery tank to my 1960 CJ-5 and an looking for a radiator cap that will work with it. Do you have one?
- A: I would go to the manufacturer that made the aftermarket tank for you.
Q: I have a 1950 Sedan Delivery with what I think is the original radiator. It looks like the radiator cap doesn’t seat correctly. It looks like the depth of the radiator neck is 1″ deep where as the rubber seals on the cap only measure 3/4″. So when the motor heats up, the cap doesn’t seal and it just goes out the overflow hose. I checked other aftermarket caps and they also measure 3/4″. Does this sound correct or am I just missing something?
- A: Sounds like you need part number#: 648746 if you have the small style. This part number is for the 2-7/8″ neck.
Q: I have a ’52 M38, the part number in the book specifies #7375030, but I’m not finding it anywhere. Will this fit?
- A: Yes as long as you have the large neck measurement above. Which you should.
Q: I have a 1953 M38A1. What exactly do I measure to find out which cap I need? Also, I have seen 7lb and 4lb caps sold as “NOS.” How do I know which is proper? Which is standard for your M38A1 replacement radiator (#805825)?
- A: We typically use a 4lb cap for the 4-134 engines. You just need to measure your neck size to confirm yours.
*EMAIL or call Mike Toll Free (1-888-648-4923) Mon-Fri, 9am-5pm EST if you have any questions about this part or restoring your Willys.