Help on replacing the heater core with A/C?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Bigo Serge · 12-21-2009, 02:03 AM

What up fellas,

I'm new here. I got a 72 cheyenne with A/C, and want to know if anyone can guide me in the easiest way to replace my leaking heater core. This isn't my first rodeo with heater cores. I just haven't had to change it on this truck, and I thought I could figure it out as I go on.
So far I have....
1. removed my glove box
2. removed the center air ducks form under the dash with the bolts.
3. removed the bolts that holds the heater core, it just won't budge.
what clips or bolts am I missing?
I have read that the inner fender has to be dropped on the non a/c trucks, is it the same for the a/c trucks? Any pictures will be greatly appreciated. Thanks for everyones information.

Charles Hettich · 12-21-2009, 07:03 PM

yeah i know on my non ac 72, i just changed the core, and i had to drop the fender and take off the hood hinge. its not that bad of a job. im not sure on the ac pickups tho

JimKshortstep4x4 · 12-21-2009, 08:45 PM

Welcome to the 67-72 Chevy Truck Board from West Michigan!

Do you have the heater core housing out? Here is a picture of the housing as looking from the inside, (it is the housing with the relay on it).

The hoses have to be disconnected as well as the housing to firewall fasteners. Once the housing is out there are two sets of clamps that hold the core in place. Usually once you get the clamps unscrewed the core is still difficult to pull out. They fit into the housing tightly and have a caulk on them to seal them in.

Jim

Bigo Serge · 12-21-2009, 08:53 PM

That is exactly where im at. The heater core housing is still attached, but I have removed the bolts that hold it to the firewall from the inside. Are you referring to the fasteners to the thin nuts that are next to the heater core hoses on the (firewall) of the engine compartment?

JimKshortstep4x4 · 12-21-2009, 09:00 PM

Look for some round headed fasteners on the inside of the heater core box. It seems like there are four of them. When you find them remove the stamped steel nuts on the engine side of the firewall.

Jim

Bigo Serge · 12-21-2009, 09:07 PM

Great!! I know what you are talking about now. Thanks for your help.

Richard H. · 12-21-2009, 08:55 PM

What Charles said about the inner fender is right ,there are one or two at the bottom you can't see or feel.

12-21-2009, 02:03 AM	#1
Bigo Serge Registered User Join Date: Dec 2009 Location: Wichita, ks Posts: 59	Help on replacing the heater core with A/C?? What up fellas, I'm new here. I got a 72 cheyenne with A/C, and want to know if anyone can guide me in the easiest way to replace my leaking heater core. This isn't my first rodeo with heater cores. I just haven't had to change it on this truck, and I thought I could figure it out as I go on. So far I have.... 1. removed my glove box 2. removed the center air ducks form under the dash with the bolts. 3. removed the bolts that holds the heater core, it just won't budge. what clips or bolts am I missing? I have read that the inner fender has to be dropped on the non a/c trucks, is it the same for the a/c trucks? Any pictures will be greatly appreciated. Thanks for everyones information.

12-21-2009, 07:03 PM	#2
Charles Hettich Registered User Join Date: Dec 2009 Location: Roscoe, SD Posts: 208	Re: Help on replacing the heater core with A/C?? yeah i know on my non ac 72, i just changed the core, and i had to drop the fender and take off the hood hinge. its not that bad of a job. im not sure on the ac pickups tho

12-21-2009, 08:45 PM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Help on replacing the heater core with A/C?? Welcome to the 67-72 Chevy Truck Board from West Michigan! Do you have the heater core housing out? Here is a picture of the housing as looking from the inside, (it is the housing with the relay on it). The hoses have to be disconnected as well as the housing to firewall fasteners. Once the housing is out there are two sets of clamps that hold the core in place. Usually once you get the clamps unscrewed the core is still difficult to pull out. They fit into the housing tightly and have a caulk on them to seal them in. Jim Attached Images __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

12-21-2009, 08:53 PM	#4
Bigo Serge Registered User Join Date: Dec 2009 Location: Wichita, ks Posts: 59	Re: Help on replacing the heater core with A/C?? That is exactly where im at. The heater core housing is still attached, but I have removed the bolts that hold it to the firewall from the inside. Are you referring to the fasteners to the thin nuts that are next to the heater core hoses on the (firewall) of the engine compartment? __________________ Pick'em up, lay'em down, Oh Yeahhh Last edited by Bigo Serge; 12-21-2009 at 09:01 PM. Reason: was not clear in my question

12-21-2009, 09:00 PM	#5
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Help on replacing the heater core with A/C?? Look for some round headed fasteners on the inside of the heater core box. It seems like there are four of them. When you find them remove the stamped steel nuts on the engine side of the firewall. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

12-21-2009, 09:07 PM	#6
Bigo Serge Registered User Join Date: Dec 2009 Location: Wichita, ks Posts: 59	Re: Help on replacing the heater core with A/C?? Great!! I know what you are talking about now. Thanks for your help. __________________ Pick'em up, lay'em down, Oh Yeahhh

12-21-2009, 08:55 PM	#7
Richard H. Spanked once Join Date: Oct 2006 Location: Intheshop, Indiana Posts: 969	Re: Help on replacing the heater core with A/C?? What Charles said about the inner fender is right ,there are one or two at the bottom you can't see or feel. __________________ The ole 350 budget build.

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