Heater Core Replacement (non-A/C) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

slow-1 · 10-14-2013, 09:44 PM

My heater core was leaking when I hooked it back up last week so I replaced it over the weekend.

I followed the suggestions from this forum AND the repair manual and it went pretty easy.

Dropped the inner fender for access to the bottom fasteners.

Propped up the hood and undid the passenger side hood hinge (after marking its location first). Used a block of wood to protect the fender, the hood and hinge slide forward enough to allow for easy removal of the heater box.

Removed:

If you ever wondered why leaves fly out of the ducts when you turn on the heat/defrost, its because there's 40 years of leaves in the heater box.

I only ran into one snag, the first core I got from Advance Auto was aluminum and did not fit, the ends of the core were not the same shape as the original so the bracket didn't fit.

Took it back and the parts girl called another store about 10 miles away and asked them to look up the same part number and they had one that was brass and correct. The guy at that store said he figures it had been on the shelf for 10 years or more.

I used plumbers putty to seal the box back to the firewall and I lubed the cables while I was at it (it was raining and I was outside so no pics of putting it back together)...now it will run you out of the truck.

Here is another thread with more pics: http://67-72chevytrucks.com/vboard/s...ad.php?t=69812

wreckedchevy · 10-15-2013, 01:56 AM

nice work, sure wish this forum existed way back when they cut my box in 2 to replace it because they thought you had to pull the fender.

Freddo · 10-15-2013, 02:17 AM

I just replaced my heater core too. Mine is 1967 C10. I got my core from Napa & it was also a slightly different size, but I got it to work. The brackets that held my core in place were in really rough shape. Does anyone know where I could find new heater core brackets?
I want to thank the people on this site who made the heater core replacement threads. They were sure a big help!

cool68 · 10-15-2013, 12:04 PM

Thanks for info

leftybass209 · 10-15-2013, 03:23 PM

Nice write-up. You are a brave man that paint looks good.

slow-1 · 10-15-2013, 10:29 PM

Quote:

Originally Posted by leftybass209

Nice write-up. You are a brave man that paint looks good.

Thanks...It looks a lot better in pictures than in person...plus, its a truck, its supposed to have character marks.

slow-1 · 10-15-2013, 10:39 PM

I wanted to ad a couple more pics that may help someone out.

Here is what it says to do in the official repair manual.

These are pictures of the area in the above drawing, you have to unhook the cable from the heat door to remove the box from the firewall.

And finally, this is the shape you want the end of your new core to look like. On the aluminum one I got first, the ends were flat which didn't allow the brackets to fit. And if you made the brackets fit, the screws would go right into the core if you used the original holes for them.

jeffro308 · 02-10-2014, 12:11 AM

This is an excellent post.

Vova · 02-10-2014, 02:18 AM

Thanks for the info. Need to do this in a few weeks.

NC_John · 02-10-2014, 06:17 AM

All good but that was not 40 yrs worth of leaves. 40 yrs worth of leaves fills the entire housing, the cowl and the kick panel vents so much you can't open or close them. Mummified mice and/or rats may or may not be included depending how much you paid for the truck!

54blackhornet · 02-10-2014, 12:48 PM

My 71 K-10 sat under a tree for 14 years, the cowl was packed to the top with leaves, the entire heater circuit was also full of mice carp . Had to replace the entire assembly. I have screens installed on both of my drivers now...

burnin oil · 02-10-2014, 01:18 PM

Quote:

Originally Posted by 54blackhornet

My 71 K-10 sat under a tree for 14 years, the cowl was packed to the top with leaves, the entire heater circuit was also full of mice carp . Had to replace the entire assembly. I have screens installed on both of my drivers now...

If you don't have AC open the vents in the kick panel from time to time. Most of the trash will blow out. There is actually a gap in the cab corner for the vent to let the trash fall out. Leaves are not to bad of a problem but pine needles are a sure thing to rust it all out. They lay down flat and hold the water in like a sponge.

*oldcane* · 02-10-2014, 01:55 PM

Just bought a '69 yesterday and it was steamy on the 2 hour ride home so I'm next.

slikside · 02-10-2014, 03:58 PM

When I did mine, I got a brass/copper one (on second try), but I still had to modify the bracket somewhat. the space between the one of the hose fittings and the tank was not enough for the bracket to fit in there like it should. So I got a torch and heated/pounded the bracket a bit to flatten it out some, and it slid right in. All normal from there on out.

Yes, this forum is awesome. Bracket screws puncturing a brand new heater core because it didn't fit right is NOT something I think I would have thought to check on my own. In fact, IIRC, I may have had to shorten one them just to be sure. But wouldn't have thought to look without the advise here.

69GMCLonghorn · 02-11-2014, 02:26 PM

Literally just wrapping up this same job on mine. The heater started smoking even when it wasn't on. When I pulled the outer heater box, the amount of leaves and stuff that came out would boggle the mind! It was so bad, I had to pull the inner heater box as well because they were packed in there too. After it snowballing into a 3 month project, it should be back on the road within a week! I can't wait!

BTW, the snowball effect went like this: Oh look, the inner fender is out. Battery box is rotten through from acid. Time to replace. Oh look, the fuel pump and water pump are leaking... Ah WTH, let's replace them too. Might as well convert to a fan clutch while I'm at it. Hey that T-stat housing is almost corroded through; Yep, let's replace it.

I've put enough perfume on the pig for one project. Time to DRIVE the dang thing! SOON!

Freddo · 02-11-2014, 04:07 PM

You wrote:
BTW, the snowball effect went like this: Oh look, the inner fender is out. Battery box is rotten through from acid. Time to replace. Oh look, the fuel pump and water pump are leaking... Ah WTH, let's replace them too. Might as well convert to a fan clutch while I'm at it. Hey that T-stat housing is almost corroded through; Yep, let's replace it.

I've put enough perfume on the pig for one project. Time to DRIVE the dang thing! SOON!

That sounds like my situation with my heater core change. The PO or someone before me had my battery held in by a couple of bungee cords. As I pulled the battery, the bottom of the box was about 80% rotted away. The bungees were not only keeping it from flying out the top, they were keeping it from dropping out the bottom. The passenger fender had been hit at some point and although it didn't look too damaged, it had moved. When I got the last bolt off the inner fender, it made a 'sproing' sound and when I attempted to put the inner fender back on, I had a heck of a time. The list is endless, but at least I'm able to drive it and enjoy it.(around town at least!)

54blackhornet · 02-11-2014, 06:53 PM

Can some one confirm the position of the core in firewall housing ? Core has both 5/8 and 3/4 outlets ?

slow-1 · 03-18-2014, 10:01 PM

Quote:

Originally Posted by 54blackhornet

Can some one confirm the position of the core in firewall housing ? Core has both 5/8 and 3/4 outlets ?

I know you asked your question a month ago and surely figured it out by now, but I will answer for those who find this thread later.

Larger outlet goes on top.

OregonNed · 03-19-2014, 12:27 AM

Great write-up I need to do this soon. Every time I hit the defrost I get particles from a nest flying out...

Motoxrrar · 03-19-2014, 01:22 AM

Quote:

Originally Posted by slikside

When I did mine, I got a brass/copper one (on second try), but I still had to modify the bracket somewhat. the space between the one of the hose fittings and the tank was not enough for the bracket to fit in there like it should. So I got a torch and heated/pounded the bracket a bit to flatten it out some, and it slid right in. All normal from there on out.

Yes, this forum is awesome. Bracket screws puncturing a brand new heater core because it didn't fit right is NOT something I think I would have thought to check on my own. In fact, IIRC, I may have had to shorten one them just to be sure. But wouldn't have thought to look without the advise here.

I purchased mine from Brotherstrucks.com it was an exact replacement for me. Didnt have any trouble at all with mounting. My brackets were in really good shape. So I had them powder coated them so they do not rust in the future if I had a leak.

They are made of just some small steel rod. Would be really easy to make them.

Vova · 03-24-2014, 07:22 PM

For those who purchased the cores that fit. Where did you get them? Having a hard time find the ones that fit the brackets.

Motoxrrar · 03-24-2014, 07:25 PM

I purchased mine from www.brotherstrucks.com

You could always have yours repaired at a radiator shop too.
I still have my old one, was planning on repairing it.

Vova · 03-24-2014, 07:28 PM

Quote:

Originally Posted by Motoxrrar

I purchased mine from www.brotherstrucks.com

You always have yours repaired at a radiator shop too.
I still have my old one, was planning on repairing it.

That's a good idea...

Motoxrrar · 03-24-2014, 07:29 PM

It won't usually cost much and it would be original still .

*gkhashem* · 10-23-2015, 05:50 PM

While this thread is great. I must say no need to remove the hood hinge.

I did my 1970 GMC today and all I needed to do was remove the inner fender.

This gave me all the access I needed. It is just nice to have a second person to help hold the gaskets in place if you get new ones.

I suggest getting those why not spend the $24.00 for a set and do it right.

Also I got a core from Classic Industries, while not cheap it fit perfect and was copper and brass. It took me about 1.75 hrs to 2 hrs to do the job.

10-14-2013, 09:44 PM	#1
slow-1 Registered User Join Date: May 2013 Location: Central NC Posts: 830	Heater Core Replacement (non-A/C) My heater core was leaking when I hooked it back up last week so I replaced it over the weekend. I followed the suggestions from this forum AND the repair manual and it went pretty easy. Dropped the inner fender for access to the bottom fasteners. Propped up the hood and undid the passenger side hood hinge (after marking its location first). Used a block of wood to protect the fender, the hood and hinge slide forward enough to allow for easy removal of the heater box. Removed: If you ever wondered why leaves fly out of the ducts when you turn on the heat/defrost, its because there's 40 years of leaves in the heater box. I only ran into one snag, the first core I got from Advance Auto was aluminum and did not fit, the ends of the core were not the same shape as the original so the bracket didn't fit. Took it back and the parts girl called another store about 10 miles away and asked them to look up the same part number and they had one that was brass and correct. The guy at that store said he figures it had been on the shelf for 10 years or more. I used plumbers putty to seal the box back to the firewall and I lubed the cables while I was at it (it was raining and I was outside so no pics of putting it back together)...now it will run you out of the truck. Here is another thread with more pics: http://67-72chevytrucks.com/vboard/s...ad.php?t=69812 __________________ 1972 Cheyene C-10 "Ole Green" My Grandfathers truck (early 70's to 1983) My first vehicle (1983) Original 350 (3 rebuilds) 700R4 from Bowtie Overdrives

10-15-2013, 01:56 AM	#2
wreckedchevy Registered User Join Date: Jun 2013 Location: billings, mt Posts: 703	Re: Heater Core Replacement (non-A/C) nice work, sure wish this forum existed way back when they cut my box in 2 to replace it because they thought you had to pull the fender. __________________ 1969 Chevy C10 2wd stepside longbox

10-15-2013, 02:17 AM	#3
Freddo Registered User Join Date: Jun 2013 Location: Richland, WA Posts: 85	Re: Heater Core Replacement (non-A/C) I just replaced my heater core too. Mine is 1967 C10. I got my core from Napa & it was also a slightly different size, but I got it to work. The brackets that held my core in place were in really rough shape. Does anyone know where I could find new heater core brackets? I want to thank the people on this site who made the heater core replacement threads. They were sure a big help!

10-15-2013, 12:04 PM	#4
cool68 Registered User Join Date: Oct 2013 Location: Stockton, CA Posts: 475	Re: Heater Core Replacement (non-A/C) Thanks for info

10-15-2013, 03:23 PM	#5
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,186	Re: Heater Core Replacement (non-A/C) Nice write-up. You are a brave man that paint looks good.

10-15-2013, 10:39 PM	#7
slow-1 Registered User Join Date: May 2013 Location: Central NC Posts: 830	Re: Heater Core Replacement (non-A/C) I wanted to ad a couple more pics that may help someone out. Here is what it says to do in the official repair manual. These are pictures of the area in the above drawing, you have to unhook the cable from the heat door to remove the box from the firewall. And finally, this is the shape you want the end of your new core to look like. On the aluminum one I got first, the ends were flat which didn't allow the brackets to fit. And if you made the brackets fit, the screws would go right into the core if you used the original holes for them. __________________ 1972 Cheyene C-10 "Ole Green" My Grandfathers truck (early 70's to 1983) My first vehicle (1983) Original 350 (3 rebuilds) 700R4 from Bowtie Overdrives

02-10-2014, 12:11 AM	#8
jeffro308 Registered User Join Date: Jan 2014 Location: Peeltown, TX Posts: 43	Re: Heater Core Replacement (non-A/C) This is an excellent post.

02-10-2014, 02:18 AM	#9
Vova Registered User Join Date: Aug 2012 Location: Los gatos ca Posts: 1,299	Re: Heater Core Replacement (non-A/C) Thanks for the info. Need to do this in a few weeks.

02-10-2014, 06:17 AM	#10
NC_John Registered User Join Date: Jul 2013 Location: Rockwell, NC Posts: 1,639	Re: Heater Core Replacement (non-A/C) All good but that was not 40 yrs worth of leaves. 40 yrs worth of leaves fills the entire housing, the cowl and the kick panel vents so much you can't open or close them. Mummified mice and/or rats may or may not be included depending how much you paid for the truck! __________________ 1970 C-10 LWB "Blu" Instagram (current build pictures) 70_nc_c10

02-10-2014, 12:48 PM	#11
54blackhornet Registered User Join Date: Jul 2008 Location: Eastern Oregon Posts: 2,290	Re: Heater Core Replacement (non-A/C) My 71 K-10 sat under a tree for 14 years, the cowl was packed to the top with leaves, the entire heater circuit was also full of mice carp . Had to replace the entire assembly. I have screens installed on both of my drivers now... __________________ 71 C-20 07 Magnum RT AWD

02-10-2014, 01:55 PM	#13
oldcane Account Suspended Join Date: Oct 2013 Location: murfreesboro, tn Posts: 109	Re: Heater Core Replacement (non-A/C) Just bought a '69 yesterday and it was steamy on the 2 hour ride home so I'm next.

02-10-2014, 03:58 PM	#14
slikside Registered User Join Date: Jun 2010 Location: San Diego Co. Posts: 1,155	Re: Heater Core Replacement (non-A/C) When I did mine, I got a brass/copper one (on second try), but I still had to modify the bracket somewhat. the space between the one of the hose fittings and the tank was not enough for the bracket to fit in there like it should. So I got a torch and heated/pounded the bracket a bit to flatten it out some, and it slid right in. All normal from there on out. Yes, this forum is awesome. Bracket screws puncturing a brand new heater core because it didn't fit right is NOT something I think I would have thought to check on my own. In fact, IIRC, I may have had to shorten one them just to be sure. But wouldn't have thought to look without the advise here. __________________ 1972 Chevy C-10, SWB, Fleet, 350/350, PS, PB, all stock, Survivor.

02-11-2014, 02:26 PM	#15
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: Heater Core Replacement (non-A/C) Literally just wrapping up this same job on mine. The heater started smoking even when it wasn't on. When I pulled the outer heater box, the amount of leaves and stuff that came out would boggle the mind! It was so bad, I had to pull the inner heater box as well because they were packed in there too. After it snowballing into a 3 month project, it should be back on the road within a week! I can't wait! BTW, the snowball effect went like this: Oh look, the inner fender is out. Battery box is rotten through from acid. Time to replace. Oh look, the fuel pump and water pump are leaking... Ah WTH, let's replace them too. Might as well convert to a fan clutch while I'm at it. Hey that T-stat housing is almost corroded through; Yep, let's replace it. I've put enough perfume on the pig for one project. Time to DRIVE the dang thing! SOON!

02-11-2014, 04:07 PM	#16
Freddo Registered User Join Date: Jun 2013 Location: Richland, WA Posts: 85	Re: Heater Core Replacement (non-A/C) You wrote: BTW, the snowball effect went like this: Oh look, the inner fender is out. Battery box is rotten through from acid. Time to replace. Oh look, the fuel pump and water pump are leaking... Ah WTH, let's replace them too. Might as well convert to a fan clutch while I'm at it. Hey that T-stat housing is almost corroded through; Yep, let's replace it. I've put enough perfume on the pig for one project. Time to DRIVE the dang thing! SOON! That sounds like my situation with my heater core change. The PO or someone before me had my battery held in by a couple of bungee cords. As I pulled the battery, the bottom of the box was about 80% rotted away. The bungees were not only keeping it from flying out the top, they were keeping it from dropping out the bottom. The passenger fender had been hit at some point and although it didn't look too damaged, it had moved. When I got the last bolt off the inner fender, it made a 'sproing' sound and when I attempted to put the inner fender back on, I had a heck of a time. The list is endless, but at least I'm able to drive it and enjoy it.(around town at least!)

02-11-2014, 06:53 PM	#17
54blackhornet Registered User Join Date: Jul 2008 Location: Eastern Oregon Posts: 2,290	Re: Heater Core Replacement (non-A/C) Can some one confirm the position of the core in firewall housing ? Core has both 5/8 and 3/4 outlets ? __________________ 71 C-20 07 Magnum RT AWD



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03-19-2014, 12:27 AM	#19
OregonNed Registered User Join Date: Dec 2012 Location: Vancouver, Washington Posts: 1,644	Re: Heater Core Replacement (non-A/C) Great write-up I need to do this soon. Every time I hit the defrost I get particles from a nest flying out... __________________ 1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop

03-24-2014, 07:22 PM	#21
Vova Registered User Join Date: Aug 2012 Location: Los gatos ca Posts: 1,299	Re: Heater Core Replacement (non-A/C) For those who purchased the cores that fit. Where did you get them? Having a hard time find the ones that fit the brackets.

03-24-2014, 07:25 PM	#22
Motoxrrar Registered User Join Date: Feb 2014 Location: Tennessee Posts: 282	Re: Heater Core Replacement (non-A/C) I purchased mine from www.brotherstrucks.com You could always have yours repaired at a radiator shop too. I still have my old one, was planning on repairing it. Last edited by Motoxrrar; 03-24-2014 at 07:30 PM.

03-24-2014, 07:29 PM	#24
Motoxrrar Registered User Join Date: Feb 2014 Location: Tennessee Posts: 282	Re: Heater Core Replacement (non-A/C) It won't usually cost much and it would be original still .

10-23-2015, 05:50 PM	#25
gkhashem Account Suspended Join Date: Aug 2015 Location: The moon Alice Posts: 93	Re: Heater Core Replacement (non-A/C) While this thread is great. I must say no need to remove the hood hinge. I did my 1970 GMC today and all I needed to do was remove the inner fender. This gave me all the access I needed. It is just nice to have a second person to help hold the gaskets in place if you get new ones. I suggest getting those why not spend the $24.00 for a set and do it right. Also I got a core from Classic Industries, while not cheap it fit perfect and was copper and brass. It took me about 1.75 hrs to 2 hrs to do the job.

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