After driving the car and letting it cool, I checked the coolant levels. The overflow tank was full but after opening the cap by the water pump I noticed it was about an inch low (AST was full). I filled up filler neck at water pump, drove it and checked again after it was cool and the water pump filler neck was an inch low again. I have not had a low coolant buzzer or any coolant coming out of the overflow tank. Any help would be greatly appreciated.

 

When your car cools off the cooling system will be under a slight vacuum so when you pull the filler cap off the coolant level will drop an inch or two. What you're seeing is normal.

 

if you find you are continuingly low by an inch or two and you add water so your buzzer won't activate you have one of 2 problems............

the simple problem:
you have a small pinhole perhaps leak ANYWHERE in your cooling system that prevents the retrieval of the coolant sent to the expansion tank.

the expensive problem:
your engine is pressurizing the coolant due to the equivalent of a blown head gasket.

your problem is most likely the former as it is a similar amount of coolan each day. your overflow tank should eventually fill up and start overflowing coolant.

go to Autozone, put down an returnable 75 dollar deposit and borrow a coolant system checker. hook it up to your AST and pressurize the system to around 15 psi. watch the needle and listen for leaks. ANY LEAK no matter where or how small will disallow your system to maintain the vacuum it needs to retreive your overflowed coolant. you will find your problem w the pressureizer. do check your AST radiator cap too.

good luck

howard coleman