Radiator cap drip

[Nicketts]

Hello. Had garage replace coolant hoses. Brought them the book so they understood the filling, burping, etc. all seems ok now except very slow drip out front of the cap after stopping. New cap about 3 yrs ago. Is this normal? Thanks.

[18Fiatsandcounting]

It's not normal. Can you tell whether the leak is coming from the cap itself, or from the fitting on the side of the neck that goes to the overflow tank? These fittings are not very robust, and it's very easy to bend them and open up a small leak, especially when working with the overflow hose. If that's the case, the only solution is to have it welded up.

But, it also could just be that your radiator cap is not sealing. They do go bad, but it should have lasted longer than 3 years. Another possibility is that you don't have quite the right cap for the radiator, as there are different sizes that appear to fit but don't actual seal as they should.

The garage where you had the work done should be able to figure out what the issue is.

-Bryan

[Nicketts]

Thanks 18Fiats! Hey I just took off the cap, and the upper rubber gasket on the cap is loose and warped. I'm hoping this is the problem. The fitting/hose to the overflow seems OK. Could it be the cap then? Thanks so much. I'm gonna order a new one, not sure which company to go with--have used them all...

[18Fiatsandcounting]

Yes, that could well be the problem. Note that there are two different size caps for the spiders, a 1.25" tall cap for the very early years, and a 1" tall cap for the later years such as yours. See:

https://autoricambi.us/radiator-cap-1971-85/

Every so often I get a cap that just won't seal, and it's not obvious why. Inferior parts from somewhere, I imagine. Buying a different brand of cap usually solves the problem.

-Bryan

[manoa matt]

Just had this same issue, was the upper gasket had a crack in it. I bought two 13lb. Gates caps from Rockauto.com for $2.42 each. Replace coolant and rad cap every 2 years, and hoses every 4 years.