my problem is that my system dumps alot of my coolent into the overflow tank, but never draws it back in. i constantly try to bleed any small amont of air that could be in there, although i have seen no sign of it. replaced my thermostat with an autozone brand (possible problem) and i have replaced both rad. cap and filler neck cap, also autozone brand.

not sure where to go from here, i suspect that some how the system does not have enough pressure to draw the coolent back from the overflow, which makes my think that the caps are the problem. anyone have experience with this problem?
-Komisor

 

check the line that goes from your radiator to your overflow tank. more than likely there is a hole in it. when a hole is created in that line it will push the coolandt through to the overflow, but when it tries to draw it the coolant back in it will suck the air through the hole in the line rather than the coolant from the overflow.

 

even if there is no visible leaking in the line???

also that is just regular vaccum line right?

 

you're right in that it's most likely a pressure problem. Mine was doing the same thing, and still is, just not as badly. I replaced my rad pressure cap with one from autozone, and that helped. After I did that, I read on here that the aem caps don't do as well as the oem ones.

Everyone is going to tell you to get the cooling system pressurized and check for leaks. Autozone has a cooling system pressurizing pump thingamajig in their loan-a-tool program, I'm going to go pick it up after work today. If I can't find any leaks, I'm going to assume it's the rad cap, and off to the mazda dealer i go :-|