1996 Volvo 850 Cooling system

DID YOU REPLACE THE THERMOSTAT? IF YOU RUN THE ENGINE AT IDLE FOR A SHORT PERIOD, THE AIR SHOULD PURGE OUT. HAVING AN AIR BUBBLE IN THE COOLING SYSTEM IS NOT GOING TO MAKE THE ENGINE OVERHEAT.

ok, so ,,to update what ive done so far, i Massaged the hoses to try and get the air out of it, i thought it was fixed drove for a lil while and it built up pressure which made the release cap release the pressure. when i unscrewed the cap the reserve filled to the max, So i tried to drive back to the house with the cap half way screwed on the reserve. It did not over heat nor did it over flow, all the way home, which was a 15 min ride. When i got home i screwed the cap on all the way while it was running and the reserve sucked dry then when i unscrewed it filled back to the max. the heat works fine screwed all the way and half way. no liquid out of tail pipe and no gas smell or oil in the anti-freeze,,,HELP!

WHEN THE ENGINE OVERHEATED, DID THE TEMP GAUGE GO INTO THE RED??

Yes it did..bu it is not overheating wen the cap is halfway screwed on.

WHEN COOLANT PRESSURE CAP IS SCREWED ON CORRECTLY, IT RAISES THE BOILING TEMPERATURE. IF YOU LEAVE THE PRESSURE CAP LOOSE, THEN THE PRESSURE OF THE COOLING SYSTEM WILL PUSH OUT THE COOLANT. DID YOU REPLACE THE COOLANT THERMOSTAT?? IF THE THERMOSTAT IS FAILING, THE COOLANT WILL NOT FLOW INSIDE THE ENGINE PROPERLY, WHICH WILL CAUSE TO OVERHEAT.

I understand..the old radiator had a crack which caused it to overheat in the first place .could that have caused the thermostat to have gone bad.bacause it didn't have this problem till I replaced the radiator. When we filled the neone we filled it by the top hose not the over flow tank. Could that have caused an air lock

ANYTIME THE ENGINE OVERHEATS, IT IS ALWAYS IMPERATIVE THAT THE THERMOSTAT GETS REPLACED. REPLACE THE THERMOSTAT AND THEN RECHECK IT.

YES, THE OVERHEATING CONDITION COULD HAVE AFFECTED THE OPERATION OF THE THERMOSTAT.

Thanks for your help..I just called the part store and put a thermostat on hold..ill replace the old one..I can take the oldone out and stick it in boiling water and it should open if its good right....

YEAH. HOWEVER, IF YOU ARE GOING TO GO THROUGH THE TROUBLE OF PULLING IT OUT, YOU MIGHT AS WELL REPLACE IT. THIS WAY YOU KNOW FOR SURE THERE IS NO PROBLEM WITH IT.

Well I changed out the thermostat and its still overheating. Any ideas

IS THE COOLING FAN TURNING ON?

Yes the fan turns on and off...I flushed the system and filled it back up water..ismelled the tank cause I saw shiney surface..it smells kuke gas so I think it is a blown headgasket

DID YOU CHECK THE CONDITION OF THE OIL? IS THERE SIGNS OF COOLANT MIXTURE?