Got a 92 civic hb, 200k. Replaced the thermostat and gave it a tune up. Still overheats when sitting too long, or in the mountains. I add antifreeze at least 2-3 times a wk. I drive it daily. Don't think it is the head gasket cause wouldn't the coolant/oil be mixing? The fan does turn on. What else could be the problem, not wanting to replace the head gasket if I don't have to.

 

Perform a cooling system pressure test to check for leaks.

 

why is it using up so much anti freeze??? a leak or bad radiator is my guess

 

Is it leaking onto the ground at all? If so, find where it's coming from. If not, it's probably the head gasket so do a leakdown test to confirm.

 

Not finding any on the ground, how do you perform the pressure test? If it was the head basket wouldn't the coolant and oil be mixing?

 

Did you properly bleed the system after the installation of the termostat?

It has nothing to do with the leak, I'm just asking.

 

Doesn't always mix with the oil. I could go straight to the cylinder and burn off. And white smoke/steam out of the tail pipe?