Home » Public Forums » GMCnet » Heater Isolation Valve (Are two necessary?)
| Heater Isolation Valve [message #350721] |
Sun, 15 December 2019 19:37  |
Melbo
Messages: 144
Registered: August 2018
Location: Albuquerque NM
Karma: 0
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I am making a plan for the replacement of my timing chain and gears. While I have to drain the coolant and remove everything in front of the timing chain and gears I figured it is a good time to do some preventative maintenance and replace all the heater and radiator and other misc hoses so I am off to a fresh start when everything goes back together. Someone who worked on this unit before me installed two shutoff valves for the heater. One is on each hose and both are manually operated by opening the hood and turning them with a wrench or other implement. I was wondering if TWO vavles are necessary. I like being sure something is going to work BUT if no water can get to the heater core OR no water can get out isn't that sufficient?? Of course all the belts will be replaced as well. While studying the way to do this I see where when you use a 100 amp alternator it is a good idea to have a two sheave pulley on the alternator. Where does the extra belt run? Is this something I should upgrade while I have the front of the engine apart. Harmonic balancer, water pump, etc will all be off so any changes would be better now instead of later.
Thanks for all the help and information with this project.
Melbo
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC
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| Re: Heater Isolation Valve [message #350722 is a reply to message #350721] |
Sun, 15 December 2019 20:50  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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One heater shutoff valve is fine. I have never figured out why some people put two there.
On double belts, simply use two belts of the same size and replace the shortest one going to the PS pump. I switched to using 1/2" wide belts because 7/16" ones are getting harder to find and many manufacturers are selling 3/8" ones which cause problems.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Heater Isolation Valve [message #350727 is a reply to message #350721] |
Mon, 16 December 2019 07:53 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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One valve stops flow for heat transfer (if vacuum shutoff doesn't seal all the way, or AC is inefficent or whatever), two valves stops all flow if the core itself gets a leak. If a problem, close valves, top it off with water or coolant, and go home to fix it there.
Same concept for the 40 feet of rubber hose that runs to rear house hot water heater in a conventional GMC floor plan. First, if you have not replaced all that hose yet, you need to. Second, if anything snatches or punctures or wears out in any of that long loop, you will lose all your coolant just like a radiator failure. One valve stops the heat transfer to the back, and two valves gives you options in different scenarios.
With either coolant loop, you can close one, or both depending on heat considerations, and fail safe considerations. If I didn't use my house hot water (and I love it being hot when I arrive for a shower) I would keep the rear loop closed off completely - not worth the risk unless you like the benefit. Using a levered ball valve you don't need tools. When checking fluids for a trip put them where you want them.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
[Updated on: Mon, 16 December 2019 07:56] Report message to a moderator |
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| Re: Heater Isolation Valve [message #350728 is a reply to message #350721] |
Mon, 16 December 2019 09:39 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Either way is a bad idea. The GM ones have a slight weep feature to circulate fresh coolant to the heatercore to minimize electrochemical corrosion Not enough to change cabin temp at all.
John Lebetski
Woodstock, IL
77 Eleganza II
[Updated on: Mon, 16 December 2019 09:40] Report message to a moderator |
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| Re: [GMCnet] Heater Isolation Valve [message #350730 is a reply to message #350728] |
Mon, 16 December 2019 10:05 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Everything you do in life can be assigned a risk factor. Being sedentary
has a risk ( more than one), as does bending over to tie your shoe laces,
or walking out to retrieve the morning paper, or strolling through a
shopping mall parking lot while viewing your cell phone screen.
It is the "risk vs benefit ratio" that trips up most of us, and
pleases
Murphy greatly.
As I age, I find myself invoking caution a whole lot more than I did
in my early years. Don't exactly know why i do that. Should be the other
way 'round. Throw caution into the wind. Won't make any long term
difference. Not going to be here long enough to care. (Grin)
Going to get in my personal auto and drive 50 miles up the interstate
to some medical appointments today, and return during rush hour traffic.
What's the risk of some bad news today? Will it make a difference? I don't
know. Gonna do it anyway. Wish me luck.
Jim Hupy
Salem, Oregon
On Mon, Dec 16, 2019, 7:40 AM John R. Lebetski via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Either way is a bad idea. The GM one have a slight weep feature to
> circulate fresh coolant to the heatercore to minimize electrochemical
> corrosion Not
> enough to change cabin temp at all.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Heater Isolation Valve [message #350732 is a reply to message #350730] |
Mon, 16 December 2019 10:46 |
Mike Kelley
Messages: 467
Registered: February 2017
Karma: -2
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Senior Member |
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Good Luck Jim H.:
Love your attitude Man!
C U down the road!
Mike/The Corvair a holic
76 Eleganza II 26’ - cross country ready
76 Glenbrook 28’ stretch - cross country ready
78 Glenbrook 26’ - project coach
Sent from my iPhone
> On Dec 16, 2019, at 10:05 AM, James Hupy via Gmclist wrote:
>
> Everything you do in life can be assigned a risk factor. Being sedentary
> has a risk ( more than one), as does bending over to tie your shoe laces,
> or walking out to retrieve the morning paper, or strolling through a
> shopping mall parking lot while viewing your cell phone screen.
> It is the "risk vs benefit ratio" that trips up most of us, and
> pleases
> Murphy greatly.
> As I age, I find myself invoking caution a whole lot more than I did
> in my early years. Don't exactly know why i do that. Should be the other
> way 'round. Throw caution into the wind. Won't make any long term
> difference. Not going to be here long enough to care. (Grin)
> Going to get in my personal auto and drive 50 miles up the interstate
> to some medical appointments today, and return during rush hour traffic.
> What's the risk of some bad news today? Will it make a difference? I don't
> know. Gonna do it anyway. Wish me luck.
> Jim Hupy
> Salem, Oregon
>
> On Mon, Dec 16, 2019, 7:40 AM John R. Lebetski via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Either way is a bad idea. The GM one have a slight weep feature to
>> circulate fresh coolant to the heatercore to minimize electrochemical
>> corrosion Not
>> enough to change cabin temp at all.
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
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| Re: Heater Isolation Valve [message #350733 is a reply to message #350721] |
Mon, 16 December 2019 11:10 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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We were told in a seminar at the GMCMI in Tucson, that it's not good to completely isolate your heater core for extended periods of time because it will contribute to corrosion and rot.
It might be wise to install two valves so that you CAN isolate it if you need to in an emergency, but it is best to circulate some water through it regularly, even with ONE manual shut-off valve.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
[Updated on: Mon, 16 December 2019 11:11] Report message to a moderator |
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| Re: [GMCnet] Heater Isolation Valve [message #350747 is a reply to message #350746] |
Tue, 17 December 2019 13:15 |
Mike Kelley
Messages: 467
Registered: February 2017
Karma: -2
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Senior Member |
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Gr8 news Jim.
Now enjoy the holidays and thank your maker!
And - thanks for sharing.
Mike/The Corvair a holic
Sent from my iPhone
> On Dec 17, 2019, at 1:05 PM, James Hupy via Gmclist wrote:
>
> I survived the latest round of tests yesterday with a big THUMBS UP. Doing
> great. They don't want to see me again unless my situation changes. Good
> news all around.
> Jim Hupy
> Salem, Oregon
>
> On Mon, Dec 16, 2019, 9:41 AM Jim Galbavy via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Jim H,
>>
>> I've the same outlook. ....but I can't bend over and tie my shoes (so
>> wear sandals here in Florida instead).
>> That I can get away with.
>>
>> Me too to see the Dr. this afternoon. Good luck with yours.
>>
>> jim Galbavy
>> '73 x-CL ANNIE
>> Lake Mary, Fl
>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
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>>
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| Re: [GMCnet] Heater Isolation Valve [message #350748 is a reply to message #350747] |
Tue, 17 December 2019 14:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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I thank my maker every day I draw a breath. By his grace I am here today,
to share my gift of knowledge with my fellow GMC owners.
Jim Hupy
Salem, Oregon
On Tue, Dec 17, 2019, 11:16 AM Mike Kelley via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Gr8 news Jim.
> Now enjoy the holidays and thank your maker!
> And - thanks for sharing.
> Mike/The Corvair a holic
>
> Sent from my iPhone
>
>> On Dec 17, 2019, at 1:05 PM, James Hupy via Gmclist gmclist@list.gmcnet.org> wrote:
>>
>> I survived the latest round of tests yesterday with a big THUMBS UP.
> Doing
>> great. They don't want to see me again unless my situation changes. Good
>> news all around.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Mon, Dec 16, 2019, 9:41 AM Jim Galbavy via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> Jim H,
>>>
>>> I've the same outlook. ....but I can't bend over and tie my shoes (so
>>> wear sandals here in Florida instead).
>>> That I can get away with.
>>>
>>> Me too to see the Dr. this afternoon. Good luck with yours.
>>>
>>> jim Galbavy
>>> '73 x-CL ANNIE
>>> Lake Mary, Fl
>>>
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
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>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
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| Re: [GMCnet] Heater Isolation Valve [message #350749 is a reply to message #350748] |
Tue, 17 December 2019 14:50 |
Mike Kelley
Messages: 467
Registered: February 2017
Karma: -2
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Senior Member |
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👍
Sent from my iPhone
> On Dec 17, 2019, at 2:46 PM, James Hupy via Gmclist wrote:
>
> I thank my maker every day I draw a breath. By his grace I am here today,
> to share my gift of knowledge with my fellow GMC owners.
> Jim Hupy
> Salem, Oregon
>
> On Tue, Dec 17, 2019, 11:16 AM Mike Kelley via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Gr8 news Jim.
>> Now enjoy the holidays and thank your maker!
>> And - thanks for sharing.
>> Mike/The Corvair a holic
>>
>> Sent from my iPhone
>>
>>> On Dec 17, 2019, at 1:05 PM, James Hupy via Gmclist > gmclist@list.gmcnet.org> wrote:
>>>
>>> I survived the latest round of tests yesterday with a big THUMBS UP.
>> Doing
>>> great. They don't want to see me again unless my situation changes. Good
>>> news all around.
>>> Jim Hupy
>>> Salem, Oregon
>>>
>>> On Mon, Dec 16, 2019, 9:41 AM Jim Galbavy via Gmclist >> gmclist@list.gmcnet.org> wrote:
>>>
>>>> Jim H,
>>>>
>>>> I've the same outlook. ....but I can't bend over and tie my shoes (so
>>>> wear sandals here in Florida instead).
>>>> That I can get away with.
>>>>
>>>> Me too to see the Dr. this afternoon. Good luck with yours.
>>>>
>>>> jim Galbavy
>>>> '73 x-CL ANNIE
>>>> Lake Mary, Fl
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
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| Re: [GMCnet] Heater Isolation Valve [message #350750 is a reply to message #350746] |
Tue, 17 December 2019 15:40 |
Olly Schmidt
Messages: 1265
Registered: February 2014
Location: Germany and Scottsville, ...
Karma: 8
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Senior Member |
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On 17.12.19 20:05, James Hupy via Gmclist wrote:
> I survived the latest round of tests yesterday with a big THUMBS UP.
Always very nice to hear good news.
--
Best regards
Peer Oliver Schmidt
PGP KeyID: 0x4196BF22
'76a 26' Eleganza II - Virginia, US
'73 23' Sequoia - Schleswig-Holstein, Germany
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Best regards
Olly Schmidt
PGP Key ID: 0x18a9 3a1f 4196 bf22
'76a Eleganza II, VA
'73 Sequoia, SH, Germany
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| Re: Heater Isolation Valve [message #350784 is a reply to message #350721] |
Wed, 18 December 2019 10:45 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Wish Daktari a merry Christmas and get the hell outa there 
And merry Christmas to you as well.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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