Home » Public Forums » GMCnet » Fixed!!!!
| Fixed!!!! [message #105963] |
Mon, 15 November 2010 16:37  |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
Karma: 0
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Fixed It!!! Drove to Ohio and DQ. using the AC. Would not switch over to heat. Found the plug on the back of the control head off compleatly! How does that happen with an engine swap??? Still wouln't work. Took the disk apart. The keeper was broke on one side and the other broke removing it. Used a nylok nut and had to ground down the head and file a new slot. Still no work. Took it all aprt and tested several times. I've got a 12v vac. pump, hand got tired. Tested the hose at the head conector with the yellow trace,,,no good. You can see 2 vac motors to the left of the glove box. The top one is the AC. Yep,,,, big leak. It was off completely. And very hard to put back???? How does this happen. Never was in there!!! There looks like there is a third one below the 2 you can see. Another vac hose headed down. The heat and defrost look like double acting with 2 motors each. One for fully closed/open with the other for 1/4 inch open or "bleeed" mode. The reason why I posted this with detail is I tried to trouble shoot this with out reading the manual and just looking at the diagram. Not untill I read the manual did I notice how the whole system work. You gotsa to have a manual!!! A hand vacume pump, gauge, extra hoses,T's of diffrent sizes, caps of multiple sizes. I keep it all in a small cheep tackle box. Get a couple of tee's that accend in size in steps for troublesooting and repairs. must have for other vehicles too. Now,,,on to the washer pump,,,no power at the pump,,,,oh well,,,,PL
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| Re: Fixed!!!! [message #105966 is a reply to message #105963] |
Mon, 15 November 2010 17:49  |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
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It's nice to know that I'm not the only one having heater issues. I took the coach out (a 75) for a 10 mile spin today, and even with the heat control all the way to the right, I still get cold air coming out of vents. I tried moving the control on the heater box itself to the open position (I assume that the flapper is hinged on the back side, but still no heat. The vacuum valve in the heater hose is open, and the hoses feel warm to the touch, so I'm puzzled. Can the heater core get airlocked so coolant doesn't flow through it? I guess it's time to start seriously troubleshooting the heating system before the winter really sets in here in Chicago.
However, I'm glad that I'm finally at the stage when I can worry about this sort of thing. The coach ran very nicely otherwise, and I am trying to take it out for short periods of exercise when I can.
George Rudawsky
Chicago, IL
75 Palm Beach
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| Re: Fixed!!!! [message #105967 is a reply to message #105963] |
Mon, 15 November 2010 18:04 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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George you say "warm". They should be hot so that you can't keep your hand on it. Could be water valve or partly blocked heater core. I've had some success with the old garden hose to the heater core run full blast in both directions and getting lots of crud out. If it starts to leak it was going to anyway.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Fixed!!!! [message #105972 is a reply to message #105963] |
Mon, 15 November 2010 18:23 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
Karma: 0
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George, had a 318ci charger that had no heat at idle. New it was time to add coolant due to a slow leek. hit the gas and heat returned. Always check the easy stuff first. coolant level. Check that air temp door. Cable operated, my cable sheath is screewed to the contol head, and the eye broke off. Had to make a 1 hole stap to secure it. Make sure you read the manual. You also might drain 2-4 gal. and pop the hoses off the valve and put an eyeball on it.,,,good luck,,,PL
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| Re: Fixed!!!! [message #105981 is a reply to message #105966] |
Mon, 15 November 2010 19:46 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| GeorgeRud wrote on Mon, 15 November 2010 17:49 |
It's nice to know that I'm not the only one having heater issues. I took the coach out (a 75) for a 10 mile spin today, and even with the heat control all the way to the right, I still get cold air coming out of vents. I tried moving the control on the heater box itself to the open position (I assume that the flapper is hinged on the back side, but still no heat. The vacuum valve in the heater hose is open, and the hoses feel warm to the touch, so I'm puzzled. Can the heater core get airlocked so coolant doesn't flow through it? I guess it's time to start seriously troubleshooting the heating system before the winter really sets in here in Chicago.
However, I'm glad that I'm finally at the stage when I can worry about this sort of thing. The coach ran very nicely otherwise, and I am trying to take it out for short periods of exercise when I can.
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George. That coolant control valve is notoriously poor. When it is closed it is not completely closed, meaning it leaks some. You will feel heat on the pipes going into the heater core even when the valve is closed. Many of us have eliminated the vacuum controlled valve completely and replaced it with a ball valve from Lowes, Home Depot, etc. If you do not want replace it with a ball valve for a test, then just temporarily remove the vacuum controlled valve and put a straight through connector in it's place.
If you have an OEM water pump or a large diameter impeller replacement water pump you should have no problems expelling the air out of the heater core system after a new ball valve or straight through connector is installed. If you have one of the smaller impeller replacement pumps you might have to drive it for a while to get all of the air out of the heater system. Some people with those smaller impellers have reported having install a bleeder or "tee" to pump the air out of them.
If you still do not have heat after installing the ball valve or straight through connector, then you need to figure out why the heat door is not moving. You can remove the front cover on the heater box to observe the movement of the door. While you are in there you probably will want to replace the foam seals on the door itself.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Fixed!!!! [message #105984 is a reply to message #105966] |
Mon, 15 November 2010 20:23 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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George,
The fitting where the heater line connects to the intake manifold has a restricted opening -- perhaps only an 1/8 inch and was clogged on my 73 coach. Are the hoses running to the hot water pre-heat and warmer than the hoses for the dash heater?
Here is info on a replacement vacuum control heater valve..
http://www.gmcmhphotos.com/photos/showphoto.php?photo=30899&title=gmc-motorhome-009&cat=4620
Dennis
| GeorgeRud wrote on Mon, 15 November 2010 17:49 |
It's nice to know that I'm not the only one having heater issues. I took the coach out (a 75) for a 10 mile spin today, and even with the heat control all the way to the right, I still get cold air coming out of vents. I tried moving the control on the heater box itself to the open position (I assume that the flapper is hinged on the back side, but still no heat. The vacuum valve in the heater hose is open, and the hoses feel warm to the touch, so I'm puzzled. Can the heater core get airlocked so coolant doesn't flow through it? I guess it's time to start seriously troubleshooting the heating system before the winter really sets in here in Chicago.
However, I'm glad that I'm finally at the stage when I can worry about this sort of thing. The coach ran very nicely otherwise, and I am trying to take it out for short periods of exercise when I can.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: Fixed!!!! [message #105986 is a reply to message #105963] |
Mon, 15 November 2010 20:53 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
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Senior Member |
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Thanks for the info, those seem like rather easy things to check.
Hopefully I will get to them before it gets too cold.
George Rudawsky
Chicago, IL
75 Palm Beach
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| Re: Fixed!!!! [message #106463 is a reply to message #105963] |
Mon, 22 November 2010 15:12 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
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Senior Member |
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Finally got around to replacing the heater control valve with a ball valve, and does it give out the heat now! On high fan, it should keep anyone sitting up front nice and toasty.
Now, on to hooking up my vacuum guage. Does anyone know offhand what size the vacuum hoses from the manifold to the carb, etc. are? I would like to pick some hose up along with the a Tee and replace all the old ones at the same time. No sense doing the job part-way just to have another hose leak after a 35 year service period!
George Rudawsky
Chicago, IL
75 Palm Beach
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| Re: Fixed!!!! [message #106469 is a reply to message #106463] |
Mon, 22 November 2010 16:28 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| GeorgeRud wrote on Mon, 22 November 2010 15:12 |
Finally got around to replacing the heater control valve with a ball valve, and does it give out the heat now! On high fan, it should keep anyone sitting up front nice and toasty.
Now, on to hooking up my vacuum gauge. Does anyone know offhand what size the vacuum hoses from the manifold to the carb, etc. are? I would like to pick some hose up along with the a Tee and replace all the old ones at the same time. No sense doing the job part-way just to have another hose leak after a 35 year service period!
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I believe for accuracy the line to a vac gauge should not be T'ed into vac line for anything that "uses" vacuum. I would T into the trans vacuum modulator. I would not use the heater vacuum supply or any of the emissions vacuum lines. I certainly would not use the cruise control vacuum connections.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: Fixed!!!! [message #106560 is a reply to message #105963] |
Tue, 23 November 2010 13:39 |
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I'm also having mediocre performance with the heater in my 73 as well. The lines to the heater core are hot so I know the core is getting hot water. Just seems the control for the ducting isn't working exactly as it should. Any ideas?
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] Fixed!!!! [message #106572 is a reply to message #106560] |
Tue, 23 November 2010 14:25 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Shan,
If you haven't got Zay Brand's "Separating Hot from Cold", go to
www.gmcws.org and download it first of all.
Be sure the cable operated temperature control lever at the driver's side of
the HVAC box is operating the hot/cold door. When that door is in the "Hot"
position, air must flow straight up through the horizontal portion of the
firewall into the duct work on top of the dash. Once in there, it will flow
either to the windshield, the dash outlets, or the floor outlets.
Which of those 3 the air exits is controlled by vacuum operated doors, but
the hot/cold door, being mechanical, and its operating lever visible, is
easiest to check first. If the air flow doesn't match the control
selection, then you know where to go next.
Ken H.
On Tue, Nov 23, 2010 at 2:39 PM, Shan Rose <defconfx@gmail.com> wrote:
>
> I'm also having mediocre performance with the heater in my 73 as well. The
> lines to the heater core are hot so I know the core is getting hot water.
> Just seems the control for the ducting isn't working exactly as it should.
> Any ideas?
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Fixed!!!! [message #106630 is a reply to message #106572] |
Wed, 24 November 2010 13:39 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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This is just a general inquiry. Is the GMCnet up & running, or is there some
kind of problem. I haven't noticed any traffic since 12:25 PM 23 hrs ago.
Jim Hupy
Salem OR
78 Royale 403
On Tue, Nov 23, 2010 at 12:25 PM, Ken Henderson <hend4800@bellsouth.net>wrote:
> Shan,
>
> If you haven't got Zay Brand's "Separating Hot from Cold", go to
> www.gmcws.org and download it first of all.
>
> Be sure the cable operated temperature control lever at the driver's side
> of
> the HVAC box is operating the hot/cold door. When that door is in the
> "Hot"
> position, air must flow straight up through the horizontal portion of the
> firewall into the duct work on top of the dash. Once in there, it will
> flow
> either to the windshield, the dash outlets, or the floor outlets.
>
> Which of those 3 the air exits is controlled by vacuum operated doors, but
> the hot/cold door, being mechanical, and its operating lever visible, is
> easiest to check first. If the air flow doesn't match the control
> selection, then you know where to go next.
>
> Ken H.
>
>
> On Tue, Nov 23, 2010 at 2:39 PM, Shan Rose <defconfx@gmail.com> wrote:
>
> >
> > I'm also having mediocre performance with the heater in my 73 as well.
> The
> > lines to the heater core are hot so I know the core is getting hot water.
> > Just seems the control for the ducting isn't working exactly as it
> should.
> > Any ideas?
> >
> >
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Fixed!!!! [message #106637 is a reply to message #106630] |
Wed, 24 November 2010 18:23 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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JimH and all.
The email server has been down...
Patrick posted a message on the forum..
Dennis
[quote title=James Hupy wrote on Wed, 24 November 2010 13:39]This is just a general inquiry. Is the GMCnet up & running, or is there some
kind of problem. I haven't noticed any traffic since 12:25 PM 23 hrs ago.
Jim Hupy
Salem OR
78 Royale 403
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Fixed!!!! [message #106645 is a reply to message #106568] |
Wed, 24 November 2010 01:16 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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Could the coils be clogged? You'll never know 'till you open up the box and look, but with air flowing through the heater core all these years it's likely that it has become dirty.
Larry Davick
The Mystery Machine
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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