Alright, so we picked up a nice little 2000 Jimmy that has a salvage title from over 60k miles ago. I had inspected frame wise, body damage, and minus a very little spot of over spray, it checked out fine.
So we got it cheap, obviously cause of the title, but whatever, It runs awesome, rides great, shifts great, blah blah blah. I know it's a salvage so I'm prepared for some electrical bugs.
But, I'm not sure where to start on this problem. Here's the deal. When the temp is over freezing outside, it's got BANGING heat. It will sweat me out.
As soon as the temp drops, the heat goes out the freeking window. Nothing but "cool" air.
The thermostat is new, the coolant is new, I've flushed the heater core twice now. When I flush it, the heat comes back. Then its gone again after sitting for a few hours. What makes this even weirder, is the second time I flushed the heater core, the heat came back. Parked the truck for a few hours, then lost the heat by that night. The next day, it had heat again. It wasn't like it was after the heater core flush, but it wasn't bone cold.
It runs at aprox 195 all time. Doesn't over heat, doesn't run cold.
What's weird is I've noticed when the blower motor is on high, and it's on Face, when the blend door if on full cold, the blower blows harder, than when it's on full hot. Weird I know.
So, where should I start on this? it sucks that when we don't need the heat, it's got it. When we do, it doesn't.
I had thought I remembered seeing somewhere that the 200o-ish body styles had a problem with the HVAC controls, but I'm not sure now.
Anybody care to help me out? I'm not sure where to go with this.
Edited 1 time(s). Last edited Friday, November 19, 2010 9:58 PM
Schaffer wrote:Blazerforum.com
Truth, I have been registered on there with the Bravada for a while now.
Only thing I can think would be the blend door not working properly...Mine does the same thing when it is on full hot, It doesn't blow as hard as when it's on cold. I feel it does that because you are forcing the air down a different passage to heat it. But mine heats up nice and quick.
Alright, I'll post over there.
Are you sure you are getting all of the air out of the lines? It is a pain sometime. Could be the mixture door sticking occasionally?
2004 Cavalier. Razzi. (Sold)
1998 Corvette. Some mods.
1992 Typhoon. Lots of mods.
1994 Civic VX 44MPG
Well, I looked over at blazerforum.com and based on the problems I'm having, my blend door is working fine.
I'm thinking that there is so much crap in the cooling system that it needs to be flushed again. It's basically like the heater core is plugging up quickly.
I was also told to check the nipple which the heater hose connects to the intake manifold, which I'm going to do in the morning.
I'm also going to burp the system, but I've been doing it by leaving the rad cap off. I'm still waiting on a answer if that's the best way to do it or if there is a better way to burp it.
Sunfiretun3r wrote: I'm thinking that there is so much crap in the cooling system that it needs to be flushed again. It's basically like the heater core is plugging up quickly.
I think that's your culprit. My Mom's 97 Bravada had this issue and the clogged heater core was the culprit. We went through 3 winters where she'd have no heat, and we would backflush the heater core and it would come back. Then clog up in a few weeks. Is this another Dex-Cool car?
If you don't mind being ghetto, you can always do the cardboard in front of the radiator bit to make it run warmer and try to get something out of it that way. Good luck with this.
Thermostat is new and tested to be good.
Yes daryl, it is a dex-cool car. Think it might be a good idea to swap it out for regular old green coolant?
I don't mind putting the cardboard in the radiator, but, I'd prefer to fix it right.
I will recommend a odd flush product.Use some lime away(yeah thats right).Drain the system,fill with distilled water and add one bottle.And YES leaving the radiator cap OFF is the best way to remove trapped air.I do this with my mazda trk,the cav and wifes honda accord.Just keep ur eye on it and use cardboard in front of the radiator speeds the process up.I would drain that and fill with water and rinse it out.And note dex is notorious for screwing up rad,and heater cores.You might consider buying both new if the flush idea does not pan out.I would.
