Heater not working in car? Please HELP!?

Question

We have a 94 Pontiac Grand Prix and it has no heat. the blower works, but only cold air comes out. It has just gotten a new radiator, and we took the thermostat out because with it in the car overheated and was smoking. we have a new thermostat.. but should we put it in, or will the car overheat again? This is our only car, and we have a baby on the way... due feb.12.. and we really need heat in that car, because we live where it is cold and we dont want baby to get sick. what could be wrong with this car, and is there any way that we can fix it ourselves, and how?

Answer 1

Sounds like your thermostat was stuck closed inititally and caused the engine to overheat. With the thermostat removed, the engine will not remain warm enough for the coolant going through the heater core to transfer any heat through the blower vents with the air that is so cold right now. Why was the radiator replaced? If it was plugged up with junk, you can bet that your heater core is probably plugged with the same junk and may need replaced as well.
Unless you can get it checked out for sure, your best bet is to put the new thermostat in and place. You can put cardboard in front of your radiator to keep too much cold air from going through it so your engine can warm up. This will still only give you heat if the heater core is not plugged up.

Answer 2

The car would heat better and faster with the new thermostat in. It should not over heat with the new thermostat, the old one was probably stuck closed. However you should get some heat in the car without the part after the engine runs awhile and gets warm. There is a valve in one of the heater hoses that opens to let hot water into the heater coil when you turn on the heat. Some of these valves are located under the hood, and some are inside of the car under the dash somewhere on the right side of the car. Some of these valves work with a cable, and some work on vacuum. It is my guess that this valve is not opening for some reason. Put in the new thermostat first sense you already have it. If that does not help, then replace the valve.

Answer 3

The thermostat allows the engine to get hot enough to produce very hot water that circulates thru the heater core. The blower then blows air over the heater core which produces warm air for the cabin of the car. If you take the thermostat out, you may not be allowing the engine to warm up sufficiently, especially in a cold climate.
Put the thermostat back in and watch the temperature closely. As the engine temperature warms, turn the blower on and see if it is blowing warm air.
If the engine starts to approach "HOT", shut the car off and let it cool for a couple of hours. If no warm air came out of the vent, you may have a clogged heater core.

If the car hasn't been properly maintained, the heater core could be clogged with rust. Sometimes the lines can congeal because people may mix the wrong types of anti-freeze. Don't mix Red and Yellow anti-freeze.

Good luck

Answer 4

Make sure the new thermostat is the right one for your car. Then install the new thermostat, making sure you have the arrow marked on it in the direction of the coolant flow. Don't install the thermostat backwards! Make sure the gasket looks good so the housing won't leak after you tighten the bolts back up.

Make sure the coolant is full and make sure to bleed any air out of the coolant system. With the engine hot, both heater hoses should be hot at the firewall with the heat on high inside the car. If only the input heater hose is hot, your heater core is plugged up and needs replacing. If both heater hoses are hot, you may have a problem with your "blend door" under the dash that lets the hot air into the car.

Answer 5

If the blower works, the heater core probably works. The Thermostat would cause it to blow cold air. Definitly but in the new thermostat because 90% of the time that is what it is. Just make sure you put the cone the right way. Theromostates are easy to replace, just get some sealant, they grey paste stuff, clean off the old housing, pop that new one in, add the sealant and replace the housing. Let sit overnight. 5 minute job, seriously. real easy. Good luck.

Answer 6

I have a 97 grand prix. Our did the same thing. We had the radiator flushed, and changed the thermostat and now it works great. you need the thermostat in if you want heat. Just be sure you put it in right (get a new one if the old one was causing the car to over heat. The valve may be stuck on the old one). the first time my husband changed it he didn't use the right gaskets and it overheated and overflowed. When he used the right gaskets it worked the way it was supposed to.
Good luck.

Answer 7

Similar thing happened to me on my Altima. It just started happening. Everything was fine last year. What I did temporarily was to let the air circulate within the car (press the button with the little car picture) This helped a little but it will fog the car soon if you keep driving several miles so switch for a short time to normal mode. Then after few minutes back to circulating the air. However, I really found out what the problem was. It was very simple. MY COOLANT WAS VERY LOW!! And the core was filled up with air instead of the hot coolant. Therefore the heat was getting generated from air-filled core rather than coolant-filled heater core. Add coolant (to the radiator or overflow bottle). Caution! DO NOT OPEN RADIATOR CAP WHEN THE ENGINE IS HOT!!

Answer 8

If it has a new radiator and thermostat, maybe they were installed wrong. Those are the only two things that I can think of that could cause the problem.

Although one time I had a car that had a cracked head gasket that burned coolant. Is your vehicle burning coolant? That might be the problem... it's not a cheap fix either, like $1200 was the cheapest I could find. I ended up scrapping the car and just getting a new one.

Good luck to you!