Heater Core Problem?

**BirdCountry02** · 12-28-2010, 06:15 PM

Question for you guys. I started having problems with my car last night, and i'm trying to figure out what it is, but I believe its the heater core. While i'm driving theres a noise coming from what sounds to be the vents/glove box. I get no heat coming out, but the a/c works fine. I don't believe the noise has any relation to the brakes or engine, and it only does it when the car is moving. Is it the heater core? Any help? And any ways to fix it?

**cammed goat** · 12-28-2010, 06:18 PM

Is there a coolant smell in the car? Is the floor wet? Your blower motor could be on its way out.

**BirdCountry02** · 12-28-2010, 06:21 PM

Originally Posted by cammed goat

Is there a coolant smell in the car? Is the floor wet? Your blower motor could be on its way out.

Neither. I have had problems with water on the floor, but it only happens when it rains

**pajeff02** · 12-28-2010, 06:21 PM

Stuck blend door? Disconnected or broken vacuum line?

What kind of noise?

**BirdCountry02** · 12-28-2010, 06:23 PM

Originally Posted by pajeff02

Stuck blend door? Disconnected or broken vacuum line?

What kind of noise?

Could be a vacuum line, it got too dark before I could check it out. Where would be best to check if it was? And i'm a newb, so when you say blend door you mean...?

**pajeff02** · 12-28-2010, 06:28 PM

Originally Posted by BirdCountry02

Could be a vacuum line, it got too dark before I could check it out. Where would be best to check if it was? And i'm a newb, so when you say blend door you mean...?

The vacuum source is on the back passenger side of the engine. You will see a few small vacuum lines in the vicinity of the PCM as well... not sure exactly which one it is. The door is what closes off the heater core from the AC system, most cars have them and they are usually vacuum operated on a GM.

**BirdCountry02** · 12-28-2010, 06:30 PM

Originally Posted by pajeff02

Stuck blend door? Disconnected or broken vacuum line?

What kind of noise?

Could be a vacuum line, it got too dark before I could check it out. Where would be best to check if it was? Its almost as if pressure is building up and can't be relieved. It's hard to explain, and i've never had a problem like it before so it's hard for me to properly explain

**cammed goat** · 12-28-2010, 06:30 PM

Try this...start the car and turn the blend knob (marked with arrow to face, floor, defrost) and listen for a hissing noise.

**BirdCountry02** · 12-28-2010, 06:47 PM

Originally Posted by pajeff02

The vacuum source is on the back passenger side of the engine. You will see a few small vacuum lines in the vicinity of the PCM as well... not sure exactly which one it is. The door is what closes off the heater core from the AC system, most cars have them and they are usually vacuum operated on a GM.

Sorry for the double post, didn't know I hit submit before checking it. I just went out and checked and I didn't see or hear any vacuum lines from what I could tell, but mind you it was dark and I used a flashlight

Originally Posted by cammed goat

Try this...start the car and turn the blend knob (marked with arrow to face, floor, defrost) and listen for a hissing noise.

Nope. Just went out and did it and there wasn't any hissing. Although when I switched from hot to cold, cold felt like it was pushing out a lot more than the other

**cammed goat** · 12-28-2010, 06:53 PM

Then Jeff might be right about the blend door being stuck.

**BirdCountry02** · 12-28-2010, 07:05 PM

Perfect! Thanks guys. You 2 are helping me out tons. How would I go about inspecting/fixing it?

**pajeff02** · 12-29-2010, 05:42 AM

Originally Posted by BirdCountry02

Perfect! Thanks guys. You 2 are helping me out tons. How would I go about inspecting/fixing it?

I have the factory service manuals for the '02 -- I can take a look tonight. Please shoot me a reminder or post in this thread this evening in case I forget.

**Cutlass** · 12-29-2010, 06:22 PM

The temp door (hot to cold) is controlled by a cable on this car. The air flow mode doors(floor, dash, defrost vents) are vacuum controlled and so is the recirc/fresh air door. So if the modes switch from floor to defrost then you don't have a vacuum or door problem there.
So now we need to figure out why your heat doesn't work and what the noise is and are the two related.

**BirdCountry02** · 12-29-2010, 06:48 PM

Originally Posted by Cutlass

The temp door (hot to cold) is controlled by a cable on this car. The air flow mode doors(floor, dash, defrost vents) are vacuum controlled and so is the recirc/fresh air door. So if the modes switch from floor to defrost then you don't have a vacuum or door problem there.
So now we need to figure out why your heat doesn't work and what the noise is and are the two related.

Well, I listened to the noise again and it sounds like either there's pressure built up, or something rattling out of place. I can't tell which it is because it only does it after the car is rolling. It sounds like its got something to do with the heating/air conditioning, but I could be wrong. My heat started to work better tonight(I don't know why) but it just started to take long to work. I don't know if the noise/heat problems coincide or not. I checked all the lines nearest the a/c unit next to the pass. firewall, and they seemed fine and I could't see/hear air escaping. Where do you think the best place to start is diagnosing the noise?

**Cutlass** · 12-29-2010, 07:02 PM

can you make and post a video of the noise?
Pinpoint as exactly as you can to where its coming from an take pic of that area, maybe?

**BirdCountry02** · 12-29-2010, 08:28 PM

Originally Posted by Cutlass

can you make and post a video of the noise?
Pinpoint as exactly as you can to where its coming from an take pic of that area, maybe?

I can try to tomorrow. Its definetely coming from the front pass side, but i'll try to get a vid up of it

**pajeff02** · 12-30-2010, 04:45 AM

Originally Posted by Cutlass

The temp door (hot to cold) is controlled by a cable on this car. The air flow mode doors(floor, dash, defrost vents) are vacuum controlled and so is the recirc/fresh air door. So if the modes switch from floor to defrost then you don't have a vacuum or door problem there.
So now we need to figure out why your heat doesn't work and what the noise is and are the two related.

Good info!

**0rion** · 12-30-2010, 06:56 AM

sounds to me like you have water backing up due to the condenser drain being plugged....had that happen on a grand prix my wife had a few years ago. Water in the floorboard after it rains and the fan making racket was what hers did. Seems like that drain may be a little different on the f-bodies though if my memory is correct. There's a drain hose on the passenger side firewall.

Also, after re-reading your post it could be a plugged heater core gurgling. What does the noise sound like? You can backflush that heater core if you suspect that's what it is and a lot of times that will work for a while.

**BirdCountry02** · 12-30-2010, 04:55 PM

Originally Posted by 0rion

sounds to me like you have water backing up due to the condenser drain being plugged....had that happen on a grand prix my wife had a few years ago. Water in the floorboard after it rains and the fan making racket was what hers did. Seems like that drain may be a little different on the f-bodies though if my memory is correct. There's a drain hose on the passenger side firewall.

Also, after re-reading your post it could be a plugged heater core gurgling. What does the noise sound like? You can backflush that heater core if you suspect that's what it is and a lot of times that will work for a while.

Ya know, it honestly has changed how it sounds to me. The thing is, it was warmer out today and everything seemed fine. the noise wasn't as bad when its cold, and it was hard to tell what it sounded like being my clamp came off so my exhaust is extra loud right now. It could be gurggling, hard to tell. It's definetely coming from around the glove box, which is why I think it could be the heater core, but the condenser could be clogged . I'll have to check the condenser drain out tomorrow. How hard is it to flush the heater core? Cause it could be that too, kinda thinking it's probably one of those 2 things