2001 chevy impala 3.4L. The car is running hot but the heater blows cold air.I changed the t thermostat but that didn't solve the problem. Please help me solve this problem or direct me to a very helpful website. if it help my top hose is hot while my bottom hose is cold also my radiator cap be cold when the car is over heating. I get no steam or bubbling sound just temp gauge going to over heated level. Thanks in advance
Why is my car running hot but heater blowing cold air.?
The no heat is a good clue that its not the thermostat. Sounds like you have a bad air pocket or a flow problem.
Is there a bleeder near the top of the engine? First thing to try is to get all the air out of the system.
Are you in a really cold area? Is it possible your anti-freeze was too weak and partially froze?
Worst case scenario would be a head gasket issue. So cross your fingers!
** here is why it wouldn't be a thermostat.
1) the thermostat is closed until a temperature is reached to open and coolant starts to flow to keep the engine cool, however the flow still goes to the heater core whether the t-stat is closed or not. This is how the heater core gets warm coolant to heat the cab even though the t-stat may have not opened. If we had to wait for a t-stat to open on a 10 degree day, we wouldn't get warm air for a very long time.
2) even if you put the t-stat in backwards, it would still be able to open to allow coolant flow. Yes the hot coolant will be touching the wrong side of the t-stat, but it will be enough to transfer heat to the spring, thus opening the t-stat. Again, you would still be getting hot coolant to the heater core in a properly flowing and operating system.
Why is my car running hot but heater blowing cold air.?
I can pretty much guarantee its the heater core. Its plugged with that god awful Dex-Cool. That is the worst coolant ever. You need to pull the heater core hoses off the engine, back flush the heater core with a water hose in the outlet side of the heater core. You may have to do it more than once. That Dex-Cool tends to gel up and clog stuff like you would not believe. It is the culprit in the basis of a lawsuit against GM for the loss of intake gaskets from Dex-Cool. I would flush that entire system and use a different coolant. It is IMPERATIVE that when you do, ALL the dex-cool must be removed from the system. It and the new coolant cannot mix at all.
Wow, I am an idiot. Disregard my post above, I didnt read the whole question. Yes, it seems as though it could be the thermostat and or the water pump. I would lean towards the t-stat though but not rule out the pump. Just changed the waterpump in a 97 Taurus cause of no heat and over heating. The impellers on the pump were worn dorn to the plate.
My first thought, did you put the thermostat in right side up,also could be a air pocket, fill cooling system up, leave off the Radiator cap while the motor is running,let it idle for a while, with the cap off.
Add coolant do not add water! Check water pump belt,make sure it is tight,and in good shape!
If the water pnmp is bad it will leak water out the bottom of pump!
Make sure you have the thermostat in properly. Sounds like you may have it in upside down. If that's not it your water pump may be bad. Look in the radiator and see if you have flow.
air in system, head gasket, t-stat in backwards, plugged radiator.
air pocket
bleed the system
Unfortunately, I have some bad news for you. You probably have a blown head gasket. The outflow from the cylinder that has the problem stops all water circulation. See if the circulation starts again if the radiator cap is removed. This will vent combustion gases and allow normal flow. So if you run the engine with the cap off, and heater function returns, and then you put the cap back on and the heater function quits, you almost certainly have a blown head gasket.
To confirm this, call around to some of your local garages. Tell them you suspect a head gasket leak and want to know if they have a chemical tester. If they do, take the car down to them and to have them run the test (shouldn't cost too much, and it only takes 5 minutes.) They place a glass tube with a rubber seal over your radiator tank opening or your expansion tank opening, put in some test fluid, and use a rubber bulb to suck air through the test fluid. If the fluid changes color, it means
there ARE combustion gases in your cooling water, which indicates a blown head gasket. What do you do then? Well, the first step would be to try one of the head-gasket-sealers-in-a-can that the auto parts stores sell. This is the cheapest for a first attempt. Will probably run you $10 to $70 depending on which magic sealer you use. If this works, you are good to go. If it doesn't, the next step will be a head gasket change.
