| Dash heater core leaking [message #91243] |
Tue, 06 July 2010 10:05  |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Took the coach for a pretrip ride this morning, and smelled that sweet antifreeze odor. When I got home, lots of antifreeze dripping out of the dash AC/heater box. I've looked on Gene's site, but can't find anything there on removing the heater core. Where can I find info on this or can anyone tell me the best procedure for getting at the heater core. Coach is a 78 Royale
TIA
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Dash heater core leaking [message #91245 is a reply to message #91243] |
Tue, 06 July 2010 10:28  |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Larry,
Here is a good picture of the heater core in the unit
http://www.gmcmhphotos.com/photos/showphoto.php?photo=14771&cat=4250
If you are planning a trip soon - why not put cut-off valves in the heater hoses. I bought them at Autozone, one 5/8 one 3/4 if I remember correctly. The older clerk said "you want the manual shut off valves they put on the ambulances".
They were gate valves, the same ones JimB uses, but some use ball valves.
Anyway, then you can repair the core upon returning from your trip.
Dennis
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: Larry <weidnerl@wwt.net>
To: gmclist@temp.gmcnet.org
Sent: Tue, Jul 6, 2010 10:05 am
Subject: [GMCnet] Dash heater core leaking
Took the coach for a pretrip ride this morning, and smelled that sweet
ntifreeze odor. When I got home, lots of antifreeze dripping out of the dash
C/heater box. I've looked on Gene's site, but can't find anything there on
emoving the heater core. Where can I find info on this or can anyone tell me
he best procedure for getting at the heater core. Coach is a 78 Royale
TIA
-
arry :)
8 Royale w/500 Caddy
enomonie, WI.
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MCnet mailing list
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: Dash heater core leaking [message #91246 is a reply to message #91243] |
Tue, 06 July 2010 10:31 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| Larry wrote on Tue, 06 July 2010 08:05 |
Took the coach for a pretrip ride this morning, and smelled that sweet antifreeze odor. When I got home, lots of antifreeze dripping out of the dash AC/heater box. I've looked on Gene's site, but can't find anything there on removing the heater core. Where can I find info on this or can anyone tell me the best procedure for getting at the heater core. Coach is a 78 Royale
TIA
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Larry: I looked at my photo shoot of cleaning the evaporator on the AC of my '76 but it really does not show how to take it apart: http://www.gmcmhphotos.com/photos/showgallery.php?cat=4048
However, as I recall, it is fairly straightforward. Remove the stuff from in front of the HVAC unit, remove the heater hoses, take the screws out of the metal cover and there it is, on the top. I was concerned about taking the evaporator out, not the heater core, so not sure if there are any tricks to that. I know the evaporator was a PITA to remove as it was sort of glued in place by some sticky cork/tar like stuff originally designed to keep air from by passing the core. I don't think the heater has that issue.
A search of the photo archives may find some better photos or comments, as well as the collective input of people here.
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Dash heater core leaking [message #91247 is a reply to message #91245] |
Tue, 06 July 2010 10:35 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Follow up to my first post
Here are the manual heater valves I used...
http://www.autozone.com/autozone/accessories/Performance/Shut-Off-Valve/_/N-269u?filterByKeyWord=manual+heater+valve&fromString=search
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: dennisfsexton@aol.com
To: gmclist@temp.gmcnet.org
Sent: Tue, Jul 6, 2010 10:28 am
Subject: Re: [GMCnet] Dash heater core leaking
arry,
ere is a good picture of the heater core in the unit
http://www.gmcmhphotos.com/photos/showphoto.php?photo=14771&cat=4250
f you are planning a trip soon - why not put cut-off valves in the heater
oses. I bought them at Autozone, one 5/8 one 3/4 if I remember correctly. The
lder clerk said "you want the manual shut off valves they put on the
mbulances".
hey were gate valves, the same ones JimB uses, but some use ball valves.
nyway, then you can repair the core upon returning from your trip.
Dennis
ennis Sexton
3 GMC
ermantown, TN
SA
-----Original Message-----
rom: Larry <weidnerl@wwt.net>
o: gmclist@temp.gmcnet.org
ent: Tue, Jul 6, 2010 10:05 am
ubject: [GMCnet] Dash heater core leaking
Took the coach for a pretrip ride this morning, and smelled that sweet
tifreeze odor. When I got home, lots of antifreeze dripping out of the dash
/heater box. I've looked on Gene's site, but can't find anything there on
moving the heater core. Where can I find info on this or can anyone tell me
e best procedure for getting at the heater core. Coach is a 78 Royale
IA
rry :)
Royale w/500 Caddy
nomonie, WI.
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Cnet mailing list
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MCnet mailing list
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Dash heater core leaking [message #91262 is a reply to message #91246] |
Tue, 06 July 2010 12:28 |
Charles
Messages: 455
Registered: January 2004
Karma: 0
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Senior Member |
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Once you are in the HVAC unit there is a small bracket
held in by one screw that you will need to remove before
you can remove the heater core. I think it took a 1/4 inch
socket and short extension to reach the screw. After that the
core pulls right out. While you are in there you will probably
want to replace the foam on the A/C / heater door. You can
just glue a piece of high density foam on the door after you
scrape off the old foam. That is if there is any old foam left
on the door.
Charles
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Charles Wersal
Duncanville, Texas
26 foot 1975 Glenbrook
Pandora's Box
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| Re: Dash heater core leaking [message #91299 is a reply to message #91243] |
Tue, 06 July 2010 17:35 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Hi Larry.
The core comes right out the front. Just remove the front cover, the two hoses, a couple of mounting screws, and you sill have it in your hand.
For you immediate trip you can get a 5/8 to 3/4 hose adapter at NAPA and just hook the two hoses together.
Option 2 is to go to the hardware store and get a ball valve and two adapters to screw into it. One for 3/4 hose and one for 5/8 hose. Hook the two hoses to the ball valve and you will be bypassed. Be sure to look in the Pex tubing area. I believe I found they fit better in our heater hoses than the barbed ones did.
I suggested the ball valve because you may want to reuse it after you get the heater core replaced to turn off the coolant flow in the summer during AC season.
It is a 10 minute job in the parking lot of Lowes, Menards, or Home Depot to bypass the heater core.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Dash heater core leaking [message #91472 is a reply to message #91398] |
Wed, 07 July 2010 21:03 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Larry wrote on Wed, 07 July 2010 11:00 |
Thanks for all the suggestions. Right after I posted the thread, I went out and pulled the hoses off of the heater core and just hooked the two hoses together. This will get me through the trips we need to make and I'll fix it this fall before our winter trip.
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That will do it for now.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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