Cooling system problems radiator cap question

oldfox

Member
Feb 19, 2009
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Hi, I have a problem I have never seen before. I can't get my cooling system to hold any pressure to speak of at all. And it wants to kick the coolant out.
I was working on it getting ready to make a overflow bottle and I noticed that when I squeeze the upper hose to see if there is any pressure building up that the coolant comes out of the over flow spout. I know that the radiator cap seals in two places. Around the top and under the spring that
keeps the system closed until the correct pressure is obtained and then it lets coolant into the over flow and the coolant goes back in the radiator as
it cools and takes up less space.--Right?-- OK I tried a new cap and it's still the same way. The radiator is an after market aluminum that I got so long
ago I forget the name brand name. It's like the neck on the radiator is to
tall and not letting it seat. SO,,,I took the lower rubber gasket off one cap and put it on a cap that already had a gasket so now it has two stacked
and the cooling system builds up pressure. But would it be OK to run it like this or might that extra gasket keep the spring to tight and build up to much pressure? Or stack them and then and go with a 10lb cap?

I was thinking maybe I could hook up a pressure gauge of some type and see where it opens with two gaskets.?
Keep in mind that the extra gasket is only about as thick as an inner tube
It's like it only need just a touch to reach.
Sorry about the long post but I thought I needed to explain it.
what would you do?
 
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Have you had this radiator installed long? Did it work without issues before?

Do you have any coolant leaks? If it's not holding pressure, there's probably an air leak some where...your guess seems to be the cap.

I don't know that I'm gonna have any real good advice for you, but if it worked before and doesn't work now, then we know it CAN work without too much trouble (hopefully).