Heater Isolation Valve

[Melbo]

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

 

[Ken B]

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

 

[tyler]

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, fop 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.

--
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC

 

[john r. lebetski]

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

 

[Jim Hupy]

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 <

> 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
>

 

[Irish Rogue]

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

>
> 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 <

>
>> 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
> Unsubscribe or Change List Options:
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[Carl Stouffer]

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 soe 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

 

[jim galbavy]

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

 

[Jim Hupy]

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 <

> 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
>

 

[Irish Rogue]

Gr8 news Jim.
Now enjoy the holidays and thank your maker!
And - thanks for sharing.
Mike/The Corvair a holic

Sent from my iPhone

>
> 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 <

>
>> 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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[Jim Hupy]

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 <

> 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 <

> >
> > 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 <

> >
> >> 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:
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>
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[Irish Rogue]

Sent from my iPhone

>
> 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 <

>
>> 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 <

>>>
>>> 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 <

>>>
>>>> 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
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[peer oliver schmidt]

> 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

 

[johnny]

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