I have the aluminum AST on my car. Ever since I installed it my coolant buzzer goes off after a couple of times driving the car and after it cools down. I check the fill cap and usually need to add about 4 ounces. The overflow tank is totally full and tends to spit out coolant when the car heats up. I check the level in the overflow and it is to the top. I do not think the AST is allowing the overflow to fill the radiator when it cools down.

I want to check my hose routing. I have the bottom of the AST going to the radiator, the thermo housing hose going to the top of the AST, and the middle hose going to the overflow. Is that correct? I have the manual that doesn't show all 3 hoses and a web site from the forum that shows the middle line going to the thermo housing/fill cap. Which is correct?

 

No. The middle hose goes to the thermostat housing and the top of the AST with the vented cap goes to the overflow bottle. The bottom goes to the radiator as you have it.

Connected your way you are actually pumping coolant from the engine into the overflow and losing coolant.

 

Thanks Damon, that is exactly what is happeining to me.

 

It'll work itself out, I had the same issue 2x, 1x in my old '94 and another in my new '93.... either way I kept a bottle of antifeeze / water mix in one of teh storage compartments, and added water as needed for about a month... less and less each time, and eventually it goes away...

It seems to be overflow / air / ast related....

-DC