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New Radiator Cap - Foam overflow

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J

JBlubaugh

Senior Member
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Hi All -

Finished off the BT7 trunk project this weekend and decided to take it for a ride around my favorite roads here in San Diego. Coming back into my neighborhood I had a gentleman crossing the street in front of me wildly pointing to a streak of foam coming out of the radiator overflow. Since I was 300 yards from home, I just drove it on into the garage. After stopping, and letting it sit for a bit, I opened the radiator and it was full of white foam. After the normal amount of time, everything cooled and the foam disappeared. Water level was down about 2-3 quarts.

This is the 1st time it has ever done this and coincides with a new Radiator cap I put on it when I did the trunk. I removed the new cap and compared to the old one and it is about 1/4" -1/2" shorter than the old cap. I'm assuming that the cap did not seal, causing a lack of pressure with water bypassing the cap to the point where the water level was lowered and it got really agitated, causing the foam. No oil in the water from what I can tell.

Are there different size neck lengths for Healey radiator caps? If so, where can I find one. The one from Moss must be a short version.

Thanks,
Jim
 
I'm assuming that the cap did not seal, causing a lack of pressure with water bypassing the cap to the point where the water level was lowered and it got really agitated, causing the foam. No oil in the water from what I can tell.

Your assumption is correct.
I suggest you go to David Knock @ British Car Specialist for the correct item for your car.
 
Jay Leno did the same thing in his Daimler SP250 video on line. He had an American cap on the radiator that was too short.
Ken
 
Re the comment that "this Jedi stuff is not really cute". I guess when you get your own website, you can make the rules. Until then try to respect someone else's point of view, and hard work in putting together a great resource. A little harmless humor never hurt anyone.

Just saying.

DB
 
Moss sells two 7 lb caps - 3/4" and 1" reach. You want the 1". Here they are:
screenshot.75.jpg
RadCaps2.JPG
 
Last edited:
davidb said:
Re the comment that "this Jedi stuff is not really cute". I guess when you get your own website, you can make the rules. Until then try to respect someone else's point of view, and hard work in putting together a great resource. A little harmless humor never hurt anyone.

Just saying.

DB
Click to expand...

Agreed it's the owner's forum and he can do what he wants, but also think the "Jedi Hopeful" designation is somewhat insulting. The others are OK, IMO.
 
Well now there was a fella that said " A rose is a rose by any name"-:angel2:
 
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