So...

for the last few weeks the heater in my 95 LS has been on the fritz. It will only occasionally blow hot air, typically when the car has been running for a while and is at highway speeds. When I come to a stop light, it starts blowing cold air again. I figured the heater core was going but just decided to put it off until the holidays.

Well this morning on the way to work (20ºF outside) I noticed that my temperature gauge was moving sort of erratically. It would heat up to near the high point, and then just as quickly drop back down to normal. The heat was not coming on.

I figured it was my thermostat, and so I picked up a new one and installed it about an hour ago. I refilled the radiator, let it run for 10 minutes and topped it off. I drove around for about 15 minutes; highway and local roads and it doesn't seem to be overheating, but the heat is still behaving eratically.

The water pump was changed about 70k miles ago and the car has 155k miles on it now. I changed my radiator hoses and heater hoses over the summer, and the heat was working until fairly recently.

I'm stumped, any ideas??

Thanks in advance to anyone who can help.

-Will

 

Sounds like you have an air pocket in behind the thermostat. I would take the radiator cap off and try to get your car to come up to temperature while it's sitting there, with the cap off and keep adding coolant as it goes down. You'll know the thermostat is open because the hose that comes from the bottom of the radiator will finally start getting hot and you'll see air bubbles in the coolant and the coolant level will drop a little, then just add more and top it off and you should have heat and a steady temp reading. By the way, with as cold as it is outside you'll probably have to rev the engine a good bit just to get it up to temp, if you take it out and drive it to get it warm (not recommended) be really damn careful taking the cap off so you don't get burned. Good luck.

 

i dont recommend reving your engine to get it up to temp either unless it is fairly warm already.. would defeat the purpose of letting a car warm up in cold weather

i could have misunderstood him tho

 

Well yea dude has a point, I wouldn't tach it out or anything I just meant the thermostat probably won't open if you just let it idle when it's all freezing outside and ****.

 

thanks for the tips....

I guess I hadn't run it long enough with the cap off after changing the thermostat. I managed to bleed some more air out of the system and the heater seems to be working again, although it still cools off a bit at stop lights. I'm going to pull the cap off and run it awhile longer after work to see if I can get any more air out.

Thanks again guys, I'll let you know if it that solves the problem entirely.

-Will

 

Yea, sometimes it's hard to get all the air out, especially when it's cold out. Has it been idling erratically as well? That would be another sign that there is an air pocket.

 

Thanks for posting what I wanted to post. I'll stick around for more answers. =]

 

Glad to help, you having similar problems?

 

um have you checked your coolant level? integras are known for their rads cracking.