Thread: Heater Core

Anyone ever done a write up on replacing the heater core? If so, can you point me to the information? If there isnt one out there then I'll just do one up here in the near future.

Next, anyone know where I can get a new one for a decent price? They want nearly $100.00 for one here locally at Advanced Auto and Autozone and I have to order it to boot.

Originally Posted by SyntheticShield

Anyone ever done a write up on replacing the heater core? If so, can you point me to the information? If there isnt one out there then I'll just do one up here in the near future.

Next, anyone know where I can get a new one for a decent price? They want nearly $100.00 for one here locally at Advanced Auto and Autozone and I have to order it to boot.

lol I don't even know where it is in a wbody. The only car I had a problem with the heater core was my 72 Chevelle and IIRC, it was on the other side of the firewall on the passenger side. I sold the car before it was repalced. but heck that was 1978 so maybe I paid to have it replaced.

Ive done one on a Grand Am, it wasnt entirely fun, but the GP one seems easier by virtue that the core lines are up higher on the firewall and appear to be accessible and removable easy enough. Its just getting to the inside portion that may be the issue.

Sounds like I got another How To in the making.

Do the "newer" cars have the same problem as the 60s and 70's cars did with heater cores leaking? I guess what I'm asking is, is it that common?

My wifes GA did but that was because they use plastic lines/tanks on the core and so they eventually crack. The GP's arent this way, all metal. My problem is that my heater core was taken out by the Dex Cool mess I went through and Ive just never replaced it. But now that the wife is driving it more, shes putting the bug in my ear to fix it. so I guess Im going to have to get that done. I just hate to drop $100 on a friggin heater core.

Just curious, whats wrong with the core? Is it clogged? How can you tell? Whats exactly not working?

Im pretty sure its clogged. It doesnt put out a lot of heat and is virtually useless for anything colder than 30* outside. I had a huge issue with Dex Cool deposits about a year and a half ago and I had to replace the radiator because the deposits had clogged up part of it. So I feel I need to replace the heater core to get it back to full capacity. It will blow warm air but its just not enough to compete with the cold temperatures we have had here.

No, and I will tell you why. I took my car in to have the radiator professionally flushed after I found out what was in it and it didnt do a thing for it. That stuff was in there and in there good. The heat of the coolant just seems to solidify it further.

Its a shame I dont already have the core cause Im also doing my ignition switch and heater blower resistor and the core is right there, I can see the housing it sits in. Oh well maybe I will repeat next weekend.

look at the bright side.....at least its not -10 out....... did you have to take the entire dash out?

Well I pulled most of the drivers side bottom section out, most of the drivers bottom section out, both seats but that was about it. That in itself was a chore but makes it easier to work on. Replacing the heater core I would pull at least one of the seats out and the center console but past that it would just be pulling all the stuff out to get to the core.

Heater cores are never fun.

Never had to do one on a GP yet, but never had much fun on my 87 or 94 Cavaliers I used to own.

I know they are tucked up, well inside the dash, behind the radio high if that gives you an idea. Here is an exploded video of mu dash when I was tracking down an electrical issue, maybe it might help some.


But if you think its clogged...might test that by disconnecting the lines that come from the fire wall, and connect under your alternator, into the aluminum bracket the alternator is bolted two. Undo BOTH lines, and let one hang down. Get you a garden hose, and make a seal between the hose and the rubber line to the heater core with your hand, and tun on the water. If it flows out, add more water pressure till thats maxed out, and its flowing out the other hose quite well. I would do this till the water if perfectly clean, and you don't see or stop seeing chunks of stuff coming out.

So thats clean...and the heats not putting out.

Then you might look to your blower motor inside the car, on the passengers side as a problem...OR as many have seen and I believe has already been suggested, look into the blower motor resistor as a problem too.

I replaced the GFs blower motor as hers finally died on her this winter, and now, her fan's OFF position is the #3 fan setting. So #4 is low, and #5 is high and thats it. I have a new resistor to install in it, so she can get her #1,2, and 3 back...but getting the time to do it...ya...working on that.

Hope that helps some.


I flushed out my car after my sisters system clogged up on her Regal.

I run the green stuff, and life worry free.

~F~

Thanks for the picture Farns, that looks fun. I saw where the heater core is at when I was under there today but it still doesnt seem like it would be giggle fest to replace. I dont think its clogged in the sense you would normally use the term. I believe its maybe partially blocked off and not flowing as much as it should because of the the Dex Cool sand crap that partially clogged my radiator and forced me to replace that. Ive run the green stuff ever since. Never will I run Dex Cool again.

I did replace the blower motor resistor today though along with the ignition switch. If I ever get to the point I have to tear my dash apart like yours, you might want to keep your eye on the news then for an abandoned GTP that went up in flames, LOL.

That charcoal color hides a lot of stuff....

Hey now, I keep my car clean. Though it was a good time to clean out all the Mike and Ike's that the girl friend spilled out of the box all under and around the seat there. LOL

What did you Dex Cool look like?

Here is my sisters Regal when we had to redo a lot of her stuff after 37,000 miles of use.



and replace her LIM gaskets, and unclog her LIM


We were able to clean out, and unclog her radiator as well once we removed it from her car. But just early last year, her transmission cooler side of it cracked, allowing coolant into the transmission fluid, and on into the transmission. So we ended up having to replace the radiator, as well as her transmission.

Thats another reason why I run an after market tranny cooler, plumbed directly into the cooler, not using anything of the OEM radiator. If it cracks inside...before you find out its cracked and leaking...your already screwed. Going on 8 years with my B&M cooler, and stainless steel braided lines, not even so much of a single leak yet. I think the reason why people stay away from a after market cooler is because they are afraid of the stories we hear of "operator error" installs gone bad.

Dex cool is worthless!

~F~

That looks horrible, my 94' prix had dexcool, original for 8 yrs(before i got it) and never did that but it did eat through the LIM gasket.....

But also in that car, I had air in the heater core, and it made my heat not work, just my $.02

Is there any chemical that would eat that gunk that he could pump through there, I mean to save you from having to remove the whole dash, like drano? flush the core afterwords btu I'm sure someone who knows more has a better answer