Heater Core Box Leaking - The 1947 - Present Chevrolet & GMC Truck Message Board Network

stevewhitmore · 12-14-2009, 05:27 PM

Hi Guys,
Well, thought I had everything fixed after 6 months of working on it (69 SB) , but the second time out when I got back I had a nice puddle of antifreeze on the floor, It appears to be coming out (dripping) steadily out of the heater box out under the hood, everything is dry inside. Does this mean I have a bad heater core and if so I need some help on how to repair it, never done a heater core before. Do I just unbolt the outside box to get to the core?
Thanks for any advise

hayhauler71 · 12-14-2009, 05:44 PM

Make sure the clamps on the heater hoses are tight and not leaking in the heater box.

LOW DOUGH · 12-14-2009, 05:47 PM

I believe you have to take the hood off to get the box off and yes the core is right inside there. I think the hood hing is in the way. I did it a long time ago and remember having to take the hood off.

The hoses are attached directly to the core.

kelsfine69 · 12-14-2009, 05:51 PM

Fenderwell should come out too..it makes it alot easier

stevewhitmore · 12-14-2009, 05:52 PM

I tightened the clamps and started it up and after awhile antifreeze started coming out from the bottom of the box.
Do you really HAVE to take the hood off to get it out?

my67chevytruck · 12-14-2009, 05:54 PM

yes iirc the heater box (fiberglass box) is boxed in by the hood hinge....

PanelDeland · 12-14-2009, 06:06 PM

Mark around the hinge and than prop the hood up with a "stick".You can then remove the hood hinge without taking the hood off.You might want to pad the windshield/cowl so it doesn't get scratchd.The heater core is easy to replace,it's getting to it that's a bear.Make sure you get the sealant for the box to firewall and go ahead and get a fan to firewall seal(it's round) while you're in there.No sense in doing it over.
You have the marks to line the hinge back up with so alignment should be easy.

LOW DOUGH · 12-14-2009, 06:15 PM

Quote:

Originally Posted by kelsfine69

Fenderwell should come out too..it makes it alot easier

oh yeah.... true

fixit-p · 12-14-2009, 06:15 PM

I did my 69 AC cab this summer, didn't have to pull the hood hinge but I did have to pull the inner fender to get to the last nut on the bottom right. It all came out from the inside of the cab.

LOW DOUGH · 12-14-2009, 06:17 PM

I am not sure if it is different... but, is this a factory a/c truck or just the standard heater/vent truck. Mine is a heater/vent. There is only a heater core out side on the firewall and it comes out form the outside under the hood..

stevewhitmore · 12-14-2009, 06:24 PM

No AC, so I think the outside box has to come out? Not sure what has to happen on the inside?

faribran · 12-14-2009, 06:31 PM

i just removed mine.... no A/C...
i unbolted the rear Inner Fender..

:-)

stevewhitmore · 12-14-2009, 06:32 PM

OK so how do you "pull" the inner fender, I see bolts under the inner fender well, is that it?

stevewhitmore · 12-14-2009, 06:34 PM

The rear inner fender?

LOW DOUGH · 12-14-2009, 06:45 PM

he means the rear of the inner finder. It's been so long sence i had mine in that i couldn't tell you were to unbolt it. All i can remember is there are bolts that go along and under the finder opening. Oh and two that attach to the inner part of the fender.

I'm thinking there are about 8 bolts.... well there are some that atach it to the radiator core support also.

better jack it up and take the wheel off. Jack it up and secure it with a jack stand and chalk the back wheels for safty

stevewhitmore · 12-14-2009, 07:13 PM

Does anything need to be done (unhooked) from the inside, the Haynes manual is not real clear on anything but it mentions a cable to unhook on the inside?

12-14-2009, 05:27 PM	#1
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Heater Core Box Leaking Hi Guys, Well, thought I had everything fixed after 6 months of working on it (69 SB) , but the second time out when I got back I had a nice puddle of antifreeze on the floor, It appears to be coming out (dripping) steadily out of the heater box out under the hood, everything is dry inside. Does this mean I have a bad heater core and if so I need some help on how to repair it, never done a heater core before. Do I just unbolt the outside box to get to the core? Thanks for any advise

12-14-2009, 05:44 PM	#2
hayhauler71 Registered User Join Date: Aug 2009 Location: St. Paul MN. Posts: 1,996	Re: Heater Core Box Leaking Make sure the clamps on the heater hoses are tight and not leaking in the heater box.

12-14-2009, 05:47 PM	#3
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Heater Core Box Leaking I believe you have to take the hood off to get the box off and yes the core is right inside there. I think the hood hing is in the way. I did it a long time ago and remember having to take the hood off. The hoses are attached directly to the core. Last edited by LOW DOUGH; 12-14-2009 at 05:47 PM.

12-14-2009, 05:51 PM	#4
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: Heater Core Box Leaking Fenderwell should come out too..it makes it alot easier __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

12-14-2009, 05:52 PM	#5
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Re: Heater Core Box Leaking I tightened the clamps and started it up and after awhile antifreeze started coming out from the bottom of the box. Do you really HAVE to take the hood off to get it out?

12-14-2009, 05:54 PM	#6
my67chevytruck Under Construction Join Date: Oct 2007 Location: Midlothian,TX (DFW) Posts: 4,555	Re: Heater Core Box Leaking yes iirc the heater box (fiberglass box) is boxed in by the hood hinge.... __________________ Heath subscribe to the board here: http://67-72chevytrucks.com/vboard/payments.php http://67-72chevytrucks.com/vboard/s...d.php?t=157669 FAQ how to's 1956 Chevy Apache 1967 C10 SWB FleetSide (under construction) 1969 K10 SWB FleetSide (Future Build) 1972 C10 SWB Stepside (Future Build) 56 chevy truck : http://www.cardomain.com/ride/2955823/1 67 truck build: http://www.67-72chevytrucks.com/vboard/showthread.php?t=281357/1 69 k10: http://67-72chevytrucks.com/vboard/s...d.php?t=389470

12-14-2009, 06:06 PM	#7
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Heater Core Box Leaking Mark around the hinge and than prop the hood up with a "stick".You can then remove the hood hinge without taking the hood off.You might want to pad the windshield/cowl so it doesn't get scratchd.The heater core is easy to replace,it's getting to it that's a bear.Make sure you get the sealant for the box to firewall and go ahead and get a fan to firewall seal(it's round) while you're in there.No sense in doing it over. You have the marks to line the hinge back up with so alignment should be easy. __________________ 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"

12-14-2009, 06:17 PM	#10
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Heater Core Box Leaking I am not sure if it is different... but, is this a factory a/c truck or just the standard heater/vent truck. Mine is a heater/vent. There is only a heater core out side on the firewall and it comes out form the outside under the hood.. Last edited by LOW DOUGH; 12-14-2009 at 06:18 PM.

12-14-2009, 06:24 PM	#11
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Re: Heater Core Box Leaking No AC, so I think the outside box has to come out? Not sure what has to happen on the inside?

12-14-2009, 06:31 PM	#12
faribran Registered User Join Date: Jul 2005 Location: AL Posts: 1,828	Re: Heater Core Box Leaking i just removed mine.... no A/C... i unbolted the rear Inner Fender.. :-) __________________ "

12-14-2009, 06:32 PM	#13
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Re: Heater Core Box Leaking OK so how do you "pull" the inner fender, I see bolts under the inner fender well, is that it?

12-14-2009, 06:34 PM	#14
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Re: Heater Core Box Leaking The rear inner fender?

12-14-2009, 06:45 PM	#15
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Heater Core Box Leaking he means the rear of the inner finder. It's been so long sence i had mine in that i couldn't tell you were to unbolt it. All i can remember is there are bolts that go along and under the finder opening. Oh and two that attach to the inner part of the fender. I'm thinking there are about 8 bolts.... well there are some that atach it to the radiator core support also. better jack it up and take the wheel off. Jack it up and secure it with a jack stand and chalk the back wheels for safty Last edited by LOW DOUGH; 12-14-2009 at 06:46 PM.

12-14-2009, 07:13 PM	#16
stevewhitmore Registered User Join Date: Mar 2009 Location: Harpers Ferry, W VA Posts: 144	Re: Heater Core Box Leaking Does anything need to be done (unhooked) from the inside, the Haynes manual is not real clear on anything but it mentions a cable to unhook on the inside? Last edited by stevewhitmore; 12-14-2009 at 07:14 PM.



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