Heater core

[pontiacgp]

Thanks for info Longroof79, my heater core is leaking underneath car, not inside car yet. Just noticed it today. Never replaced one, but got to now. Appreciate the coaching on being patient and not getting frustrated. Bad about getting frustrated. Guess I’ll go purchase one tomorrow.

when you get the new one check the soldering joints where the tubes meet the core. I had a new one start leaking right after installation due to the soldering joint cracking when the tubes were moved a bit installing the hoses. They didn't use very much solder so I redid the joints

 

[MrSony]

There is a little weep hole in the hvac box underneath to let any coolant drain on the ground, telling you there is a problem. it only really starts filling the cabin when the entire cavity is full of coolant. It's not super hard to replace it, but it's time consuming. If you think you got all the screws, check again.

 

[Mikey]

when you get the new one check the soldering joints where the tubes meet the core. I had a new one start leaking right after installation due to the soldering joint cracking when the tubes were moved a bit installing the hoses. They didn't use very much solder so I redid the joints

Thanks for the heads up. Don’t think the one I got is going to fit. It’s a Spectra Premium. Made the guy at Oreilly’s double check. He assured me it was the right one. The tubes on mine are horizontal, 3/4 on left, 5/8 on right, the one he gave me the tubes are vertical. Probably end up taking it back.

 

[Mikey]

There is a little weep hole in the hvac box underneath to let any coolant drain on the ground, telling you there is a problem. it only really starts filling the cabin when the entire cavity is full of coolant. It's not super hard to replace it, but it's time consuming. If you think you got all the screws, check again.

Thanks, I’ll look carefully for all the screws. Never installed one, but gonna give it a try. Thanks again!

 

[commandercool86]

Thanks for the heads up. Don’t think the one I got is going to fit. It’s a Spectra Premium. Made the guy at Oreilly’s double check. He assured me it was the right one. The tubes on mine are horizontal, 3/4 on left, 5/8 on right, the one he gave me the tubes are vertical. Probably end up taking it back.

When I first bought my ElCo back in 2004, the heater was stuck on. So I bought a plastic 5/8 to 3/4 adapter (Part #47080) and bypassed the heater core in the hellish Phoenix summers, and pluged the hoses back in for winter or trips up north

 

[Mikey]

There is a little weep hole in the hvac box underneath to let any coolant drain on the ground, telling you there is a problem. it only really starts filling the cabin when the entire cavity is full of coolant. It's not super hard to replace it, but it's time consuming. If you think you got all the screws, check again.

Worked a couple of hours on my ‘85 Regal this evening getting ready for the heater core installation. Got the windshield trim out of the way, screen off, fan motor out, and all the screws out. Not bad at all, but looks like the worst is ahead tomorrow. Think it’s going to be a big pain in the azz getting the top of the heater box off. All of that black sealer is going to be tuff to cut through all the way around it. Hopefully I can get it off without messing it up. Thanks to all of you guys for all the tips. They were very helpful. Thankful for the forum!!

 

[airboatgreg]

It is not a difficult job to replace the heater core. Couple hard to find screws. Don't have to remove blower motor. Take your time and make sure you put ground strap back on the core or you may get electrolysis and cause the core to corrode prematurely.

 

[Mikey]

It is not a difficult job to replace the heater core. Couple hard to find screws. Don't have to remove blower motor. Take your time and make sure you put ground strap back on the core or you may get electrolysis and cause the core to corrode prematurely.

It is not a difficult job to replace the heater core. Couple hard to find screws. Don't have to remove blower motor. Take your time and make sure you put ground strap back on the core or you may get electrolysis and cause the core to corrode prematurely.

Airboatgreg....didn’t know about blower motor, but got it cleaned up good anyway. I’ll be sure to get strap back on. Thank you.

 

[Mikey]

It is not a difficult job to replace the heater core. Couple hard to find screws. Don't have to remove blower motor. Take your time and make sure you put ground strap back on the core or you may get electrolysis and cause the core to corrode prematurely.

Need a little more help. Finally found the correct heater core, got top off of box, got it all cleaned up inside. I’m not getting air flow from a/c vents, only floor and defrost, so is there anything I need to check that could be causing that problem inside the box before I reinstall everything?

 

[Longroof79]

Mikey, go ahead and install the heater core and reinstall the top and screen.
The problem that you describe has nothing to do with the actual heater core installation.
Check for vacuum lines that may be disconnected...or broken.
Btw, I'd recommend using some 3M strip caulk to re-seal the HVAC box top.
Do not use silicone sealer. It stays pliable and doesn't harden.
Another cause that I've found with blend door flaps not opening properly is your actual heater control on the dash. Vacuum is routed to the control and when changing functions. I've had the same issue with mine and ended up replacing the dash control. I went thru a few before finding one that worked normally. I believe its the small rotary wheel that uses rubber to help guide the vacuum flow. They become compromised over time and do not seal as well.

Check both functions on the control. Maximum and normal. Sometimes switching to maximum will open up the proper doors and direct the air to the forward vents.