i havw a 98 chev lumina and it is running hot.I replaced the therm, the heat is blowing cold whats wrong.?

Question

my car is still running hot and the air blows cold most the time ive put in antifreeze what else can be wrong.

Answer 1

The clue here is the heat is blowing cold!!! It will blow cold when there is no coolant in the heater core. This tells me either it is low on coolant, or it is not circulating. Remove the thermostat, and put it into a pan of boiling water on the stove. Remove it from the water with something that won't burn you. Now watch the thermostat to see if it closes as it cools down, if it doesn't this means it never opened to begin with. Check to make sure the thermostat is installed correctly (not backwards) and that it is the correct temperature for your engine. You can also drill a small 1/8 inch hole in the side of the thermostat to relieve the pressure and prevent an air lock. The bleeder (purge) valve is around your thermostat housing and it should be left open while you are filling the radiator/recovery tank. You want to park the vehicle with the front end high enough to get the bleeder valve higher than the rest of the vehicle. In other words; air will work its way to the highest point and stay there. If this is inside the engine, then you get an air lock. You need to check to make sure you installed the correct coolant for your vehicle, and that it is mixed properly to your owners manual. When the engine gets warmed up enough to open the thermostat, turn off the engine, and run your hand around the radiator to see if the top, bottom, and center of the radiator is hot to the touch, if its not then you got air in the system, and must continue to bleed it until it doesn't. Let the engine cool completely down to air temprature, remove the cap, and see if you can see the coolant, if not add more until you can. After you have ran it till its hot, turn it off, and let it set for 15-20 minutes, and squeeze the radiator hoses. They should still be firm, if not you still have a leak in the system somewhere letting the pressure fall off. If the system is not staying pressurized you will need to do a pressure test to see if the system, and the cap are good. I think if you do all of this, you will find the problem. Just remember, if the heater hoses aren't getting hot to the touch, then the coolant is not circulating properly. If if didn't run hot before you worked on it, then it MUST be something you did or didn't do to cause this problem, or the thermostat is no good.
Glad I could help you. Good Luck!!!

Answer 2

i own a repair shop,and its possible that it might have an air bubble in it causing the coolant not to circulate good in it,,this happens a lot when people change the thermostat in a car,,there's a procedure for filling it,and most people don't follow it,,but that's what it sounds like is happening to it,,if that turns out not to be it,,check and make sure the water pump is circulating the coolant good in it,,i have seen the fins on the water pump wear off in them,and the pump will never leak a drop of coolant,,good luck i hope this help,s.

Answer 3

BE CAREFULL HERE!!!!!
You can crack cylinder heads if you do this wrong.There is a special bleeding proceedure that involves filling a cold engine with the 2 small 7 mm bleeder screws open-fill until coolant comes out the bleeder screws-then run engine with rad cap off until thermostat opens.top up coolant and install cap.

Answer 4

did you bleed the air out of the cooling system after changing the thermostat? if not you may want to do that as it can cause damage. If you did bleed the system you may be looking at a blown head gasket.

Answer 5

air locked . park facing up hill open rad start car let run for 30 min while you stand and watch with water anf fill as ness you will see air bubbles coming out

Answer 6

low coolant (leak), blown head gasket, or most likely, just a bad water pump.