| Engine running cooler than the T'stat?? Ideas ? [message #314988] |
Tue, 21 March 2017 12:31  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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My engine is running cooler thant the thermostat setting.
This has been going on for a while, but:
1 - I though it was my imagination.
2 - I suspected the gauge calibraion.
Well, I did the pot on stove test of the 160 and 195 T'stats and both were in spec.
I was sure I put the 195 back in. I just checked and 160 is in the parts box.
Both the panel gauge and the new Digipanel agree tht 180 is about all it gets to....
And it might not stay there.
I have had T'stats fail open and one fail closed. How this happens, I don't have a clue.
There is no solid valve in the heater circuit, but we are also not getting heat in cab.
Any Ideas??
Matt - about half past Illinois on the way to Shawnee
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Engine running cooler than the T'stat?? Ideas ? [message #314989 is a reply to message #314988] |
Tue, 21 March 2017 12:35  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Matt, you have more cooling than you have heat. Big trucks have shutters to
restrict air flow. Might try some cardboard and zip ties.
Jim Hupy
On Mar 21, 2017 10:32 AM, "Matt Colie" wrote:
> My engine is running cooler thant the thermostat setting.
>
> This has been going on for a while, but:
> 1 - I though it was my imagination.
> 2 - I suspected the gauge calibraion.
>
> Well, I did the pot on stove test of the 160 and 195 T'stats and both were
> in spec.
>
> I was sure I put the 195 back in. I just checked and 160 is in the parts
> box.
>
> Both the panel gauge and the new Digipanel agree tht 180 is about all it
> gets to....
> And it might not stay there.
> I have had T'stats fail open and one fail closed. How this happens, I
> don't have a clue.
> There is no solid valve in the heater circuit, but we are also not
> getting heat in cab.
>
> Any Ideas??
>
> Matt - about half past Illinois on the way to Shawnee
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: Engine running cooler than the T'stat?? Ideas ? [message #314990 is a reply to message #314988] |
Tue, 21 March 2017 12:49 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Seen this when it is cold out. Also driving into wind.
Trade me? I would rather have 160 then my random getting hot.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Engine running cooler than the T'stat?? Ideas ? [message #315006 is a reply to message #314988] |
Tue, 21 March 2017 19:13 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Try a different 195. I bet the amount of throttle opening it gives you in a static pot and in the engine with water pump fluid pressure is different. May I suggest trying a Stant Superstat. Pintle type for better control. My Tahoe would feedback cycle overshooting and then overcooling gauge moving up and down at steady cruise load. Superstat made it rock solid stabile temp
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Engine running cooler than the T'stat?? Ideas ? [message #315007 is a reply to message #314988] |
Tue, 21 March 2017 20:25 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Do you have the water heater hooked up to the engine?
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Matt
Colie
Sent: Tuesday, March 21, 2017 12:32 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Engine running cooler than the T'stat?? Ideas ?
My engine is running cooler thant the thermostat setting.
This has been going on for a while, but:
1 - I though it was my imagination.
2 - I suspected the gauge calibraion.
Well, I did the pot on stove test of the 160 and 195 T'stats and both were
in spec.
I was sure I put the 195 back in. I just checked and 160 is in the parts
box.
Both the panel gauge and the new Digipanel agree tht 180 is about all it
gets to....
And it might not stay there.
I have had T'stats fail open and one fail closed. How this happens, I don't
have a clue.
There is no solid valve in the heater circuit, but we are also not getting
heat in cab.
Any Ideas??
Matt - about half past Illinois on the way to Shawnee
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
_______________________________________________
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
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Engine running cooler than the T'stat?? Ideas ? [message #315020 is a reply to message #314988] |
Wed, 22 March 2017 10:32 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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I would next shoot the side tank right by the upper hose to get a reading on coolant leaving engine. If it's 180 or so the stat is not doing it's job. The current gen of stats and rad caps are made from thinner and thinner metal to save pennys. My Jeep XJ started running at 210 yesterday while 40 outside and the overflow level was higher than I remember. I replaced the cap as the poppet valve spring had failed open allowing coolant to freely come and go to the overflow. The thinness of the new cap was stunning. A thin metal stat that is slighly deformed from shipping and handling may be junk though newer and working in the bench test scenario.
John Lebetski
Woodstock, IL
77 Eleganza II
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