Radiator Cap

[Deleted User]

The upper gasket on the radiator cap from my '52 Hornet is worn out. Is there a modern cap that will work (deep enough to engage the bottom seal) or can the upper gasket be replaced/refurbished?

mars55

Try a Stant 10206. It is a 7 psi cap.

[Deleted User]

NAPA BK 703-1411. 7# 3/4" deep Likely a Stant cap anyway.

RonS

Don, the correct cap for the 50 -53s is AC RC-3 7#, Stant R-6 7# is also a fit. However, make sure that the ring seal pushs against the ridge in the radiator neck. I used a 10206 and realized that the spring loaded seal was a bit short to reach the ridge and therefore had no pressure. The exact measurement in the cap from the upper seal to the lower seal is 1"( AC uses only a metal upper seal, where as Stant has a rubber seal on the upper section above the spring). You can by a Stant a lot cheaper on Ebay. The formally stated caps also fit 40-47 Buicks, 39-40 Cadillac and some 40-41 Packards. Warning! I just bought a new repro from Cars Inc.( Buick Parts) for $32. Beautiful cap, but I thought the spring was a bit strong, so I tested it... held pressure to 16 lbs when it released. Bad deal. I returned it. They probably got a batch of 13# springs in their 7# RC-3s. Ron

Lee ODell

Can't hurt to test the new 7 lb cap. My new Stant for the 52 tested at 5 lbs. The 52 never comes close to hot so I let it stay. I have Walt's kit on it.

Lee O'Dell

[Deleted User]

I bought the NAPA cap and it measured exactly. It appears to fit OK, but I will post after we have tested it.

Don

RonS

Don, does the lower seal meet the ridge in the radiator neck? Place a film of oil on the ridge then clean any residue on the cap seal. Turn down the cap fully seated. Remove it and some oil will appear around the caps lower seal if is actually the correct depth. What is the brand and part number ?