'94 Chevy Lumina Heater Problem

I was driving home from college last night and my heater didn't put out the heat like it had been doing for the past few years that I have had the car in my possesion. Last night, the temp was around 0 degrees F, however, before when it was this cold, I would always have plenty of heat. The air coming out of the vents was warm at best but not hot like it usually is. Any suggestions?? Do i just need to cover up part of my radiator or is the a possibility of a stuck thermostat? Or something worse?? Please help!

My first guess would be a thermostat stuck close. Does the car run a little hot. I'd replace the thermostat first because they are cheap anyways. Unless its been a lot colder out then before, the water temp has to get up to a certain temp before it will open up and let coolant flow through so you have heat.

just thought of it, but also if the themostat is stuck open, I think it would take longer to warm up, but wouldn't overheat because coolant is still allowed to flow through the engine.

Thanks Kenseth17 for your reply. When I was driving home (6 hour trip) The heat gradually became cooler and cooler. I do not think it's overheating because the dummy light never came on, however, I don't have temperature guage which would give me a better indication of what is going on. I think I'm going to take it to a mechanic today and have the thermostat replaced and see if that does the trick. Thanks for the help.

Andrew

Don't take that car to no mechanic. It cost less than $10 to buy a thermostat. Do it yourself! If you don't know how, buy a Haynes manual for $16 at Advanced Auto. Total for the job = ~$26.. Taking it to a mechanic = $50+ for the 20 minute job.

Anyways, a thermostat stuck open won't prevent heat. The heat comes directly off the heads and flows down into the heater core, which then blows the heat into the cabin. If the thermostat was closed, the dummy light would of indicated overheating occuring, and you wouldn't have heat since no water would be able to flow. Check the thermostat.

One way to check and see if it's stuck opened is, crank up the car and let it idle for about 2-3 minutes. Squeeze the upper radiator hose. You'll be able to feel water in it if the thermo is stuck open. If you feel nothing then the thermo is fine.

Went and picked up a thermostat from mechanic shop, went back to my garage and replaced the thermostat myself. It did the trick. I have a LOT of heat now and car runs really good. Thanks for all the help!

Andrew

B.T.W The old thermostat was gummed up and stuck open. Thanks again!