1969 C-10 Heater question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mjm0103 · 01-02-2007, 11:33 AM

Wow this board is awesome!

My son just bought a 1969 C10 w/ factory A/C for his 1st car. It runs great, but needs some tinkering with here and there. I've learned a tremendous amount already from reading this board. It's given me the courage to dive into the car deeper than I would normally feel comfortable with.

Our first task is to try to get heat into the truck. The blower blows great, but no heat. (A/C doesn't blow cold air either...but that's a task for another time) Also, when we move the "temperature" lever all the way to the right for heat, the lever would not stay in the far right position. It would move back about 1/4 to 1/2 the way. We spent a few hours cleaning out 30+ years of leaves, debris etc. from the vents plus putting in new vent and defrost hoses (the old ones were brittle and cracked) under the dashboard. That ended up giving us "luke warm" air after running the truck for :30 minutes. Also I'm not sure why, but after cleaning out that debris, the "temperature" lever now stays all the way to the right like it's supposed to when we push it over. I would like to get in behind the heater core to clean out any debris there, but I am not sure the best approach. I got under the dashboard and opened up the diverter box to where I could see the heater core inside. I'm not sure if the best way to get "behind" (the other side) the heater core is to completely remove the housing underneath the glovebox thats bolted to the firewall or if the only way to clean out leaves and debris would be from under the hood.

When I was under the dashboard I saw 2, maybe 3 bolts holding the diverter housing to the firewall. Those came off easy enough. But there are several round headed bolts with what look like metal slip on clips as well that appear to be holding the diverter box to the firewall. I tried slipping off one of the clips but it didn't seem to want to slip off. Again, it appears that these hold the housing to the firewall, but I'm not real sure. Does anyone know if removing this housing would give me access behind the heater core? If so, how do I get the danged thing unbolted from the firewall?

Since the truck has A/C the heater core box under the hood has more plumbing to it than a non-A/C. Most of the threads I've read here discuss non-A/C heater core removal, so I'm reluctant to start unbolting under the hood until I'm clear on the steps involved.

At this point all I want to do is make sure there's no blockage in the heater core. The vents were literally packed solid with debris so I'm suspecting to find similar pileups by the heater core.

If I can do that and still don't get heat, my next steps will be to replace the Thermostat since it's simple enough to do. (I did notice after running the truck for an hour that the temperature gauge barely rose past the "cold" mark...it definitely did not rise to half way between cold and hot as I would have expected) The radiator fluid level is fine. Also after running the truck for an hour, I felt all the plumbing going in and out of the heater core under the hood. They all felt about the same temperature. One wasn't hotter/colder than any of the others. Any other thoughts?

Thanks again for a great board.

Ken

JimKshortstep4x4 · 01-02-2007, 11:54 AM

Removing the heater core to clean it will help. I would suggest flushing it out also. There are probably more leaves in the cowl area to be cleaned out. (We make up and install 1/4" hardware screes under the cowl to stop the leaf problem).

The round head bolts that you see are studs that have nuts on the outside, (underhood side of the firewall).

A service manual and assembly manual are nice books to have if you are going to work on your truck yourself as they contain a wealth of information.

Jim

mjm0103 · 01-02-2007, 12:51 PM

Thanks, I do plan on getting service/assembly manuals as well.

Ken

JimKshortstep4x4 · 01-02-2007, 04:44 PM

Good luck on your heating problem and welcome to the board!

Jim

notmrgoodwrench · 01-02-2007, 05:21 PM

hey there welcome from arkansas ....just wanted to let you know that i just bought a new heater core for my truck and it was only like 20 bucks i think, so if it needs a new one then it shouldnt cost you an arm and a leg

mjm0103 · 01-02-2007, 05:50 PM

$20 bucks! that's good news. New/used? thanks. Did you get that local or off the internet? I'm sure there got to be a good local retailer in DFW where I can find parts.

jbon64 · 01-02-2007, 07:11 PM

http://67-72chevytrucks.com/vboard/s...ht=heater+core

check this post out , it might help . also , at the top of the page is a search function . type in heater core and you should get a list of all the other stuff that has been posted in the past . hope this helps

mjm0103 · 01-02-2007, 10:04 PM

Thanks jbon64, that thread helped a great deal. I stopped by Pep Boys on the way home and pickeup up the Haynes 67-87 Chevy Pickup repair manual. Between the forum threads and the manuals I'll be unstoppable. (or so I like to think)

Haynes was the only manual PepBoys had. Anybody recommend any other manuals?

dave2953 · 01-02-2007, 10:22 PM

I like my factory service manual I have for my 68. I got it for cheap on ebay, but I was pretty lucky. It's a little more specific than the Haynes as it doesn't cover such a broad range of years. I think some of the vendors sell them but they cost a bit more than a Haynes or Chilton.

FarmTruk · 01-02-2007, 10:17 PM

Unstoppable...that's the right attitude right there ladies and gentlemen. Good luck with tinkerin', and...

Welcome from Wallburg, NC.

notmrgoodwrench · 01-02-2007, 11:30 PM

i got mine at either oreilly or autozone i cant remember and i thought they had gave me the wrong price when i called cause it sounded too cheap to me but got there and that was the price.....good luck to you on this

**WorkinLonghorn** · 01-04-2007, 03:39 AM

[QUOTE That ended up giving us "luke warm" air after running the truck for :30 minutes.][/QUOTE]
Check that the truck has a thermostat mounted and that it is not stuck open. Some uninformed owners remove this in the belief that this will keep the truck from overheating.If there is no thermostat then the coolant may not be hot enough to heat the air fully in the heater.-cougar.
GMC '69 Custom Camper
Longhorn

mjm0103 · 01-04-2007, 09:25 AM

I got under the hood last night and found shut-off valves on the hoses going into and coming out of the heater core. One on the in-coming coolant and one on the out-going coolant hose. Both valves were closed. When I opened them we got heat! Yahoo! I'm still going to change the thermostat and get in the heater core to clean out leaves etc. but it looks like the valves did the trick.

FarmTruk · 01-04-2007, 02:07 PM

Why on earth would a PO install shut-off valves going to/from the HC?

PanelDeland · 01-04-2007, 06:04 PM

FarmTruk,you have obviously never been in the Dallas area during the summer.Any extra heat is way too much.mjm,the vendors on the BB here will have just about any part the part stores don't carry.The cowl vent is a true leaf catcher and the screens mentioned above will help keep the crap out of the heater AC vents.In fact most BB vendors carry screens in stainless and powdercoat for the cowl.They have mounting points and work well.

jimmydean · 01-04-2007, 07:16 PM

The PO just removed the hoses and plugged the outlets on my truck because the core leaked like crazy. Maybe the shut off was easier?

01-02-2007, 11:33 AM	#1
mjm0103 Registered User Join Date: May 2006 Location: Dallas Posts: 10	1969 C-10 Heater question Wow this board is awesome! My son just bought a 1969 C10 w/ factory A/C for his 1st car. It runs great, but needs some tinkering with here and there. I've learned a tremendous amount already from reading this board. It's given me the courage to dive into the car deeper than I would normally feel comfortable with. Our first task is to try to get heat into the truck. The blower blows great, but no heat. (A/C doesn't blow cold air either...but that's a task for another time) Also, when we move the "temperature" lever all the way to the right for heat, the lever would not stay in the far right position. It would move back about 1/4 to 1/2 the way. We spent a few hours cleaning out 30+ years of leaves, debris etc. from the vents plus putting in new vent and defrost hoses (the old ones were brittle and cracked) under the dashboard. That ended up giving us "luke warm" air after running the truck for :30 minutes. Also I'm not sure why, but after cleaning out that debris, the "temperature" lever now stays all the way to the right like it's supposed to when we push it over. I would like to get in behind the heater core to clean out any debris there, but I am not sure the best approach. I got under the dashboard and opened up the diverter box to where I could see the heater core inside. I'm not sure if the best way to get "behind" (the other side) the heater core is to completely remove the housing underneath the glovebox thats bolted to the firewall or if the only way to clean out leaves and debris would be from under the hood. When I was under the dashboard I saw 2, maybe 3 bolts holding the diverter housing to the firewall. Those came off easy enough. But there are several round headed bolts with what look like metal slip on clips as well that appear to be holding the diverter box to the firewall. I tried slipping off one of the clips but it didn't seem to want to slip off. Again, it appears that these hold the housing to the firewall, but I'm not real sure. Does anyone know if removing this housing would give me access behind the heater core? If so, how do I get the danged thing unbolted from the firewall? Since the truck has A/C the heater core box under the hood has more plumbing to it than a non-A/C. Most of the threads I've read here discuss non-A/C heater core removal, so I'm reluctant to start unbolting under the hood until I'm clear on the steps involved. At this point all I want to do is make sure there's no blockage in the heater core. The vents were literally packed solid with debris so I'm suspecting to find similar pileups by the heater core. If I can do that and still don't get heat, my next steps will be to replace the Thermostat since it's simple enough to do. (I did notice after running the truck for an hour that the temperature gauge barely rose past the "cold" mark...it definitely did not rise to half way between cold and hot as I would have expected) The radiator fluid level is fine. Also after running the truck for an hour, I felt all the plumbing going in and out of the heater core under the hood. They all felt about the same temperature. One wasn't hotter/colder than any of the others. Any other thoughts? Thanks again for a great board. Ken

01-02-2007, 11:54 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: 1969 C-10 Heater question Removing the heater core to clean it will help. I would suggest flushing it out also. There are probably more leaves in the cowl area to be cleaned out. (We make up and install 1/4" hardware screes under the cowl to stop the leaf problem). The round head bolts that you see are studs that have nuts on the outside, (underhood side of the firewall). A service manual and assembly manual are nice books to have if you are going to work on your truck yourself as they contain a wealth of information. Jim

01-02-2007, 12:51 PM	#3
mjm0103 Registered User Join Date: May 2006 Location: Dallas Posts: 10	Re: 1969 C-10 Heater question Thanks, I do plan on getting service/assembly manuals as well. Ken

01-02-2007, 04:44 PM	#4
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: 1969 C-10 Heater question Good luck on your heating problem and welcome to the board! Jim

01-02-2007, 05:21 PM	#5
notmrgoodwrench Registered User Join Date: Dec 2006 Location: arkansas Posts: 49	Re: 1969 C-10 Heater question hey there welcome from arkansas ....just wanted to let you know that i just bought a new heater core for my truck and it was only like 20 bucks i think, so if it needs a new one then it shouldnt cost you an arm and a leg

01-02-2007, 05:50 PM	#6
mjm0103 Registered User Join Date: May 2006 Location: Dallas Posts: 10	Re: 1969 C-10 Heater question $20 bucks! that's good news. New/used? thanks. Did you get that local or off the internet? I'm sure there got to be a good local retailer in DFW where I can find parts.

01-02-2007, 07:11 PM	#7
jbon64 Registered User Join Date: Jan 2006 Location: sidney , illinois Posts: 312	Re: 1969 C-10 Heater question http://67-72chevytrucks.com/vboard/s...ht=heater+core check this post out , it might help . also , at the top of the page is a search function . type in heater core and you should get a list of all the other stuff that has been posted in the past . hope this helps __________________ hey.....smell my finger 64 nova wagon , 63 nova convertible Last edited by jbon64; 01-02-2007 at 07:13 PM. Reason: more info

01-02-2007, 10:04 PM	#8
mjm0103 Registered User Join Date: May 2006 Location: Dallas Posts: 10	Re: 1969 C-10 Heater question Thanks jbon64, that thread helped a great deal. I stopped by Pep Boys on the way home and pickeup up the Haynes 67-87 Chevy Pickup repair manual. Between the forum threads and the manuals I'll be unstoppable. (or so I like to think) Haynes was the only manual PepBoys had. Anybody recommend any other manuals?

01-02-2007, 10:22 PM	#9
dave2953 Dave's not here, man Join Date: Jun 2004 Location: Winder, Georgia Posts: 2,000	Re: 1969 C-10 Heater question I like my factory service manual I have for my 68. I got it for cheap on ebay, but I was pretty lucky. It's a little more specific than the Haynes as it doesn't cover such a broad range of years. I think some of the vendors sell them but they cost a bit more than a Haynes or Chilton. __________________ - 2014 VW Jetta - 2015 VW Jetta - 1966 Ford F-250

01-02-2007, 10:17 PM	#10
FarmTruk In Memoriam... Join Date: Nov 2006 Location: Wallburg, NC Posts: 1,216	Re: 1969 C-10 Heater question Unstoppable...that's the right attitude right there ladies and gentlemen. Good luck with tinkerin', and... Welcome from Wallburg, NC. __________________ '68 C10 SWB 307ci 2BBL *FarmTruk Pics Here* *"You know, doing what is right is easy. The problem is knowing what is right."*

01-02-2007, 11:30 PM	#11
notmrgoodwrench Registered User Join Date: Dec 2006 Location: arkansas Posts: 49	Re: 1969 C-10 Heater question i got mine at either oreilly or autozone i cant remember and i thought they had gave me the wrong price when i called cause it sounded too cheap to me but got there and that was the price.....good luck to you on this

01-04-2007, 03:39 AM	#12
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,883	Re: 1969 C-10 Heater question [QUOTE That ended up giving us "luke warm" air after running the truck for :30 minutes.][/QUOTE] Check that the truck has a thermostat mounted and that it is not stuck open. Some uninformed owners remove this in the belief that this will keep the truck from overheating.If there is no thermostat then the coolant may not be hot enough to heat the air fully in the heater.-cougar. GMC '69 Custom Camper Longhorn

01-04-2007, 09:25 AM	#13
mjm0103 Registered User Join Date: May 2006 Location: Dallas Posts: 10	Re: 1969 C-10 Heater question I got under the hood last night and found shut-off valves on the hoses going into and coming out of the heater core. One on the in-coming coolant and one on the out-going coolant hose. Both valves were closed. When I opened them we got heat! Yahoo! I'm still going to change the thermostat and get in the heater core to clean out leaves etc. but it looks like the valves did the trick.

01-04-2007, 02:07 PM	#14
FarmTruk In Memoriam... Join Date: Nov 2006 Location: Wallburg, NC Posts: 1,216	Re: 1969 C-10 Heater question Why on earth would a PO install shut-off valves going to/from the HC? __________________ '68 C10 SWB 307ci 2BBL *FarmTruk Pics Here* *"You know, doing what is right is easy. The problem is knowing what is right."*

01-04-2007, 06:04 PM	#15
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: 1969 C-10 Heater question FarmTruk,you have obviously never been in the Dallas area during the summer.Any extra heat is way too much.mjm,the vendors on the BB here will have just about any part the part stores don't carry.The cowl vent is a true leaf catcher and the screens mentioned above will help keep the crap out of the heater AC vents.In fact most BB vendors carry screens in stainless and powdercoat for the cowl.They have mounting points and work well. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"



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01-04-2007, 07:16 PM	#16
jimmydean Registered User Join Date: May 2005 Location: Beaverton, OR Posts: 3,728	Re: 1969 C-10 Heater question The PO just removed the hoses and plugged the outlets on my truck because the core leaked like crazy. Maybe the shut off was easier?

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