92 GMJ JIMMY BUBBLING RADIATOR

I have a 92 Gmc Jimmy. recently( within the last 4 months) I have changed the water pump and radiator in the truck. last weekend When i had the radiator changed my mechanic said that my head gaskets were bad in teh truck because there was air bubbles in the radiator. he couldn't do the work because he doesnt do that kind of job.. what I want to know is.. if anyone knows .. is that the problem. if not what else might it be.. and how expensive it is to fix and can ti be done ourselves without killing us.. thank you Does it run bad, overheat or have white steam out the exhaust? You replaced the radiator why?? if you are not experiencing any of the above symptoms I would not run out and start replacing head gaskets. A few visible bubbles in the radiator might not warrant the head gasket replacement cost if no other symptoms are present. it is running rough now.. the day before the radiator was changed it overheated on me and stalled.. we replaced the radiator because there was a leak on the side that couldn't be fixed as far as since then.. like i said it runs rough(sounds more like there is an exhaust leak then anything) and as far as overheating goes.. it hasn't actuallty over heated but twice in the last week the temp gauge has flashed overheated but once i turn my heater on the temp goes down and stays down.. we looked at the truck yesterday and there was a small puddle of antifreeze by the thermostat.. could that be causing the bubbles as well? Hi: If you have no other symptoms as the other post suggests, then I believe that you have air trapped in your cooling system. You may also have a defective thermostat.

After doing cooling system work on some vehicles, air can become trapped inside the system. I have sometimes replaced the thermostat Car Repair Talk's forum.