Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...

leaky radiator cap

July 09, 2018, 03:35:14 pm

I've had a problem with coolant leaking from the filler neck for a while and have bought new caps that had been recommended on the forum.  I measured the distance from the filler hole top to the seat where the edge of the cap seal makes contact.  It is 3/4".  I then measured the distance between the two gaskets on the cap and it was also 3/4".  This did not allow the spring to compress and allowed the coolant to leave the system.  Also, the boiling point of the coolant was not raised, since there was no pressure created by a relaxed spring.

I've left a message with James at FT, hoping that I can get a good part number for the cap.  If anyone has some info on this it would be helpful.  I've read about "slobbering" radiator caps in the archives, but did not find a recommended cap.

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Re: leaky radiator cap

Reply #1 – July 09, 2018, 08:22:17 pm

Howdy Sven,  This is what I replaced mine with.  Also carry a spare.
Radiator Cap
NAPA part #:  703-1427
Good Luck, Dave A

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Re: leaky radiator cap

Reply #2 – July 09, 2018, 09:42:55 pm

You could cut the lower rubber seal from one of your extra caps and install it below the cap to thicken the seal.

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Re: leaky radiator cap

Reply #3 – July 10, 2018, 08:52:08 pm

FT verified that  NAPA part #:  703-1427 was the recommended cap.  This was the one I had been using for a year.  I bought a new one and found that it required a little more pressure to put on.  Looks like the problem has been solved, since it did not leak going through some pretty steep grades this morning.

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