I have a 85 Montero with 2.6l four banger and five speed tranny .... has AC but not hooked up and no belt installed.

The heater makes good interior heat .... very good as a matter of fact. So good thermostat ???

I am losing antifreeze somewhere ...... at the recovery bottle mostly .... I can find no other leaks. Don't seem to be any antifreeze in the oil ... or oil in the antifreeze.

Every so often .... more and more with the onset of cold weather .... the coolant recovery bottle lid just seems to blow off the bottle .... there goes my antifreeze in a cloud of steam ... once this happens the temp gauge will go up (but not into the red) and the heater temp gets less ... less but not cold .... still warm.

I have watched coolant flow thru the radiator with the cap off and the flow don't look real good .... the water pump is only 'bout a year or so old. With the cap off and radiator full the flow continuously pushes coolant out of the radiator .... it never seems to quit till the radiator is about a half a gallon or so low ????

So what's up ??? Sticky thermostat ? Bad radiator cap ? Hoses seem to be fine ??? water pump don't seem to leak or make noise. Heater works good . I dunno ????

I'm gonna replace the thermostat and rad cap just for good measure but ... well this is kindof weird .... and I work with a weird coolant system on Pontiac Fieros all the time ... who knows <img src="/forums/images/graemlins/zombie.gif" alt="" />

Something is causing an excessive buildup of pressure in the system and it's blowing off the cap on the recovery bottle ??????? <img src="/forums/images/graemlins/scared.gif" alt="" />