im a mechanic and i recently did some work on my 92 prelude with f22 single cam motor, head gasket was blown so i did a thermostat water pump timing belt intake and head gasket. got the head milled and cleaned cause it needed it put it all back together and coolant is now bubbling up through the reservoir really hot. so i put in a nother thermostat with a good one and it open closes bled it out right and still does it?! any help id appreciate

 

when you had the work done on the head did they pressure test it for leaks/cracks? kinda sounds like compression entering your cooling system through a crack, improperly installed/defective gasket... my first step would be to obtain a sniffer for your coolant to see if it is actually exhaust gas in there. if its not I'd be looking into a water pump leak on the suction side although thats unlikely. if you cant get a sniffer pull your plugs, see if any show signs of coolant burning in there.

 

yeah i was leaning torward a defective head gasket cause the one i put on from autopart international was slightly different from the stock one. odd but ill look into it. im hoping for no cracks or anything. my buddy at the machine shop said he looked over the head when i took it to him and he said everything looked great.

 

Have u checked your fans or the sensors? They may not be cooling down the radiator like they should and overheat it? Just my two cents