I had to put a new water pump housing on my 88 n/a... and i've slowly watched the coolent over flow jug get fuller and fuller and today out over flowed.. dont know if there is air in the system? or bad rad cap? It's not over heating at all. can anyone help? thanks

 

Get a new oem radiator cap.

Did you reuse the radiator hoses? If you are using oem clamps, make sure that the clamps are exactly in the same place as when you took them off. Put them in the existing indentions in the hoses.(this can cause a vacuum leak)

If that doesn't cure it, do the cold crank bubble test to check for blown coolant seals.

If it passes that test, you may have a leak in the tube to the overflow tank; the coolant expands out into the tank, but when the engine cools, the leak in the line allows are to seep in and break the vacuum. Some of the coolant will fail to return to the rad. Each time you drive, the process repeats until the overflow tank is full. The car will eventually overheat. You can remove the tank and pour it back into the radiator for the short term.


If that doesn't cure it, you have a vacuum leak somewhere else. You just have to eventually find it.

Good luck.

 

I would replace the hose to the reservoir and the rad cap. I bet that fixes your problem.