Nipple on top of overflow tank leaks. System has been pressure tested, all caps replaced, hoses replaced, and I never smell any antifreeze nor do I have any white smoke, but I know that the coolant in the overflow tank never comes back to the system. I can see the coolant leaking around the neck of the hose that goes to the AST, but how do you fix this without buying a new tank?

 

If you have leakage around the AST, it could be the AST itself or the cap on the AST. Do you have a stock or aftermarket AST?

The overflow tank (ie, the clear plastic one in the fenderwell) will leak out of the top by design if it's full. It should NEVER be full, though.

If coolant is pushing to the overflow tank but not getting sucked back in, check the rubber hose from the AST to the overflow tank for leaks. If it's leaking around the top of the AST, that leak could also cause coolant recovery not to work. If you have to get a new AST, do so - this problem can easily cause overheating and cost you a motor!

Dale

 

It's not leaking around the Pettit AST, but from where the AST hose connects to the overflow tank. I know that there is a vent hole between the neck and the hose connection for the AST, but should it leak where the nipple that's hooked onto the hose goes into the overflow tank???

 

Oh, and the overflow tank always has the same amount of fluid in it. I have never seen it low.

 

My AST started leaking between the top sealing surface and the pressure cap. I decided to eliminate the damn thing.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/asi-ast-509284/

 

There should be "NO" leak from the hose on the AST to the coolant recovery tank. If fluid is comming out then it will be replaced by air when it cools. You need to find out why coolant is comming from this area. your level in the recovery tank should change depending on engine temerature, (higher when hot, lower when cool) I would venture to guess you've had to add coolant to the system after driving it.

 

I have found that it's best to start with the simple fixes when dealing with the 7. I took the overflow bottle off the car and emptied, cleaned and reinstalled. I was having the light go off every two days. I have not had the light go off in a week now and it's all because I had TO MUCH COOLANT IN THE OVERFLOW TANK!!!!!! I read that you shouldn't put to much coolant into the tank, but thought this was an unimportant note, but it turned out to be a very worthy issue. Remember SEARCH to forum and START with the SIMPLE fixes!!!!!!