Heater Core Repair

[HyperBuzzin]

Well, I think I have a leak in my heater core.

At first I thought the coolant smell was the leak in my rad, but lately, when I leave work at 3am, after about a mile the windshield starts to fog up.

And during the day, if I have the AC on, then move the temp selector even just a little bit to the warm side, I get a smoke machine effect outta the vents.

 

Sooo, what all is involved in pulling the heatercore?

The truck is a '99 GMC Jimmy, 4x4, 5spd, 4.3 Vortec.

 

Thanks for any info

 

 

 

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[HyperBuzzin]

No one's had to pull their heater core???

[HyperBuzzin]

Anyone??

[HyperBuzzin]

One more try here.

Any help is appreciated.

[HDChuck01]

I had an '85 pickup with the 4.3 and the heater core was inside the truck under the passenger side of the dash. It was not too hard to pull it just a bunch of screws holding all the plastic together under there. After that it was easy to undo the two hoses to the core and take it out and out a new one in. I'm not sure about the smaller pickups/suvs but I don't think it will be too tough.

[HyperBuzzin]

I had an '85 pickup with the 4.3 and the heater core was inside the truck under the passenger side of the dash. It was not too hard to pull it just a bunch of screws holding all the plastic together under there. After that it was easy to undo the two hoses to the core and take it out and out a new one in. I'm not sure about the smaller pickups/suvs but I don't think it will be too tough.

 

Thanks for the info, Chuck.

With the way things are going right now, I haven't really even had time to look at it.

 

When I first noticed the troubles, I considered just using some of the powdered radiator leak sealer.

I'm guessing the leak can't be too bad (atleast right now) seeing as some of the people I've talked to ask if it's leaking onto the passenger floor area, but it isn't. And I haven't noticed anything leaking on to the ground either.

 

It's always something!!

[atboley]

The dash has to be pulled out, then the whole HVAC module(where the heater core sits) needs to be pulled out b4 you can get access to it, ive done enough of them that ive got it down to about maybe 4-5 hrs, but for your first time, and no instructions or power tools, could take you days

[atboley]

The dash has to be pulled out, then the whole HVAC module(where the heater core sits) needs to be pulled out b4 you can get access to it, ive done enough of them that ive got it down to about maybe 4-5 hrs, but for your first time, and no instructions or power tools, could take you days

[vxaxv17]

Never done one in a jimmy but I replaced 1 in my 88 3500. I didnt really notice any coolant on the passenger floor either until i pulled up the carpeting and heat shield. There was a good half inch of coolant all over the floorboard. That matting smelled REAL good let me tell ya ;)

 

anyway, i just disconnected the hoses under the hood going through the firewall and clamped them together with a piece of pipe. This way i could still drive the truck albeit with no heat... Then find all the screws that hold the plastic housing on. I believe they were all under the passenger side of the dash but there might have been a few going through the firewall itself. getting the plastic housing in and out was the hardest part really. It certainly helped to pull the glove box out so you could get another hand in there and actually see what you are doing. I did not have to disassemble the dash itself though. remove heater core and install new one. Make sure the parts place actually gives you the right core! The one i was given had the intake and output pipes angled slightly which made it almost impossible to fit back into its spot. Get everything bolted back up, reconnect hoses and your good to go.

 

Just out of curiousity i pressure tested the old core to see where the leak was. there were 3!

 

Good luck.