Car overheats when heat is put on. both fans

Thermostat may be bad,staying open and not letting coolant heat build up to heat vehicle.

probably not . There are fuses to check and a relay to check as well as the coolant temperature sensor to check . If the engine overheats when you have the heater on it suggests an air lock in the cooling system . Have the system pressure bled along with all the other checks.

Does this problem occur at idle? If so, does the cooling fan work? If the fan does not work the engine will overheat at idle and not overheat while moving. If you had the thermostat out why did you not replace it? For the cost it really isn't worth re-installing. If the fan works you may have a water-pump problem or a restricted cooling system, which may be as simple as no air-flow through the radiator. Look for excessive dirt, leaves, etc in the cooling fins of the rad. And don't forget to check for the same in the AC heat-exchanger.

your electric radiator fan not working check your fuse under the hood by your battery or a relay in the same fuse box.

Have the FAN CLUTCH checked. they are a common failure. Get a AC DELCO or the part from the dealer. Why was the radiator replaced? Heater work OK? A/C works OK?

I would recommend that you bleed all air out of the cooling system. The bleeder valve is located on top of the engine. Once engine starts to overheat or when you can hear bubbling back into the overflow bottle, turn car off and open bleeder valve. If you see bubbling you have air in your system. Bleed the system a couple of times and see if this helps.A heat sensor sending unit which controls activation of the electric fan could also have failed.But if the heat sensor is properly working then check the radiator cap is it properly fitted or got loose.If its loose it will release the pressure and car will overheat.But if the radiator cap is properly closed.Then its time to check the HEAD GASKET.As you have replaced the head gasket still get it checked is it overheating very quickly or is the head gasket placed properly also check the coolant level in the car. Thanks. you can rate this solution and show your appreciation.

you can try this, on the exhaust manifold there is a heat sensor you can replace this or take off the connection and with a small piece of electrical cable strip both ends put into the connection and that will put the fan on , if this fails then the fan itself is at fault [driver87]

try washingthe raditor at a car wash wash thre the engine compartment to the outside. clean the ac fan condensor then check that the fan is not loose next replace the anitfreeze if it's more than two years old, and the radiator cap if it still does it replace the thermostate gasket, these are the most common problems for over heating. you could have a clutch fan bad too but do the other stuff first it's cheeper.

cOOLING fAN tURNS ON @ 210-230 dEG. tEMP sENSOR bAD & OR fAN relay cAN cAUSE THIS pROBLEM

possible blown head gasket