Home » Public Forums » GMCnet » [GMCnet] What do those in the hot SW do for engine thermstats?
| [GMCnet] What do those in the hot SW do for engine thermstats? [message #320009] |
Wed, 05 July 2017 12:26  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
Karma: 11
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My new Digi Panel in our latest 78 Royale is showing higher temps then I was running in our former 78 Royale. Now on this trip. The temps have come up a little more. I think this latest increase is a thermostat issue. The 403 now has about 6000 miles on it. The thermostat is a 195. I'm thinking of dropping that temp. We don't leave when it's real cold. Our GMC sets in it's garage that's at 70 degrees all year long. If we leave on a cooler day. The engine isn't needing to come up from -35 below. So does 180 seem right for my situation? I'm also thinking that during the rebuild that the PO had done. The builder put a car water pump in. Think the water pump is coming up. Bob Dunahugh
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| Re: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320011 is a reply to message #320009] |
Wed, 05 July 2017 12:38  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Bob,
You're going to get all kinds of opinions on thermostat temperatures, from
none, to fixed orifice, to 165*F on up to the RECOMMENDED 195*F. Remember
that higher operating temperatures, regardless of what you may hear, =
higher efficiency. Later model vehicles run even higher for that reason.
I do, and will, stick with GMC's 195*F. And my Cad 500, with aluminum
radiator, runs at 193*F to 197*F under almost all circumstances,
coast-to-coast, towing or not, mountains or not, hot or cold ambient.
JWID,
Ken H.
On Wed, Jul 5, 2017 at 1:26 PM, Bob Dunahugh wrote:
> My new Digi Panel in our latest 78 Royale is showing higher temps then I
> was running in our former 78 Royale. Now on this trip. The temps have come
> up a little more. I think this latest increase is a thermostat issue. The
> 403 now has about 6000 miles on it. The thermostat is a 195. I'm thinking
> of dropping that temp. We don't leave when it's real cold. Our GMC sets in
> it's garage that's at 70 degrees all year long. If we leave on a cooler
> day. The engine isn't needing to come up from -35 below. So does 180 seem
> right for my situation? I'm also thinking that during the rebuild that
> the PO had done. The builder put a car water pump in. Think the water
> pump is coming up. Bob Dunahugh
>
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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] What do those in the hot SW do for engine thermstats? [message #320012 is a reply to message #320009] |
Wed, 05 July 2017 12:57 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Like Ken stated, you will get all opinions.
I dropped to a 185 thermostat, and even though I do not live in the south, I have been very happy with that. I was told to run that in the summer years ago to solve my running hot problem that turned out
To be a backwards fan. I still am fine running the 185 vs a higher temp one.
Heater airflow is about worthless in my 75, so in the winter time I do not think there is any loss for the gmc running a cooler thermostat. The furnace warms the coach in the winter. I do know that in a jeep, 10 degree thermostat does make a difference on heating when it is sub zero.
My coach sits outside in the winter time, i have a magnet heater that gets plugged in if I plan on starting it up in sub zero.
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: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320015 is a reply to message #320009] |
Wed, 05 July 2017 13:18 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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I put a 160 in the 23', it normally ran 175 and rose to ~~200 pulling Culowee. The heater would run you out of it. The 26' has a 180, and it opins 180 until it hits a climb, goes up to 210. I expect the goes up figure to drop below 200 when the new fan goes in.
--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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| Re: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320017 is a reply to message #320011] |
Wed, 05 July 2017 14:13 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Yabbut, that radiator is also cooling the transmission. I'm not sure
there's much of an efficiency difference in the engine between 180 and 195,
but if the 180 keeps the tranny 15 degrees cooler also, then that's okay
with me.
Rick "stirring the pot" Denney
On Wed, Jul 5, 2017 at 1:38 PM, Ken Henderson
wrote:
> Bob,
>
> You're going to get all kinds of opinions on thermostat temperatures, from
> none, to fixed orifice, to 165*F on up to the RECOMMENDED 195*F. Remember
> that higher operating temperatures, regardless of what you may hear, =
> higher efficiency. Later model vehicles run even higher for that reason.
>
> I do, and will, stick with GMC's 195*F. And my Cad 500, with aluminum
> radiator, runs at 193*F to 197*F under almost all circumstances,
> coast-to-coast, towing or not, mountains or not, hot or cold ambient.
>
> JWID,
>
> Ken H.
>
>
> On Wed, Jul 5, 2017 at 1:26 PM, Bob Dunahugh wrote:
>
>> My new Digi Panel in our latest 78 Royale is showing higher temps then
> I
>> was running in our former 78 Royale. Now on this trip. The temps have
> come
>> up a little more. I think this latest increase is a thermostat issue.
> The
>> 403 now has about 6000 miles on it. The thermostat is a 195. I'm
> thinking
>> of dropping that temp. We don't leave when it's real cold. Our GMC sets
> in
>> it's garage that's at 70 degrees all year long. If we leave on a cooler
>> day. The engine isn't needing to come up from -35 below. So does 180 seem
>> right for my situation? I'm also thinking that during the rebuild that
>> the PO had done. The builder put a car water pump in. Think the water
>> pump is coming up. Bob Dunahugh
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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| Re: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320018 is a reply to message #320017] |
Wed, 05 July 2017 15:13 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I will admit that Rick has a point there: The P-30 chassis manual's
predicted ATF life at 175*F is 100,000 miles vs only 50,000 at 195*F.
However, since my transmission pan temperature seldom reaches 155*F, and
that only well into a long day's drive, I'll accept an average age
somewhere around that 100,000 miles. I might even change it before then.
:-)
(I assume 100,000 mile ATF is still useable with acetone as a penetrating
oil.)
Ken H.
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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] What do those in the hot SW do for engine thermostats? [message #320022 is a reply to message #320017] |
Wed, 05 July 2017 15:32 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Rick,
Don't forget the thermostat only controls the temperature in the engine.
The efficiency of the radiator will control the temperature in the discharge
tank where the tranny cooler is located. Before I lost my tranny pan temp
sender, my pan temps were in the 130 degree range. That's a Cad 500
with an aluminum radiator pulling a 4-door tracker here in the flatlands.
No one, including me, has bothered to check the discharge temp of the
aluminum radiator to know how good it really is. But I like it, yes I do.
Gary Kosier
77PB w/500Cad
Newark, Ohio
--------------------------------------------------
From: "Richard Denney"
Sent: Wednesday, July 05, 2017 3:13 PM
To:
Subject: Re: [GMCnet] What do those in the hot SW do for engine thermstats?
> Yabbut, that radiator is also cooling the transmission. I'm not sure
> there's much of an efficiency difference in the engine between 180 and
> 195,
> but if the 180 keeps the tranny 15 degrees cooler also, then that's okay
> with me.
>
> Rick "stirring the pot" Denney
>
> On Wed, Jul 5, 2017 at 1:38 PM, Ken Henderson
> wrote:
>
>> Bob,
>>
>> You're going to get all kinds of opinions on thermostat temperatures,
>> from
>> none, to fixed orifice, to 165*F on up to the RECOMMENDED 195*F.
>> Remember
>> that higher operating temperatures, regardless of what you may hear, =
>> higher efficiency. Later model vehicles run even higher for that reason.
>>
>> I do, and will, stick with GMC's 195*F. And my Cad 500, with aluminum
>> radiator, runs at 193*F to 197*F under almost all circumstances,
>> coast-to-coast, towing or not, mountains or not, hot or cold ambient.
>>
>> JWID,
>>
>> Ken H.
>>
>>
>> On Wed, Jul 5, 2017 at 1:26 PM, Bob Dunahugh
>> wrote:
>>
>>> My new Digi Panel in our latest 78 Royale is showing higher temps
>>> then
>> I
>>> was running in our former 78 Royale. Now on this trip. The temps have
>> come
>>> up a little more. I think this latest increase is a thermostat issue.
>> The
>>> 403 now has about 6000 miles on it. The thermostat is a 195. I'm
>> thinking
>>> of dropping that temp. We don't leave when it's real cold. Our GMC
>>> sets
>> in
>>> it's garage that's at 70 degrees all year long. If we leave on a
>>> cooler
>>> day. The engine isn't needing to come up from -35 below. So does 180
>>> seem
>>> right for my situation? I'm also thinking that during the rebuild
>>> that
>>> the PO had done. The builder put a car water pump in. Think the water
>>> pump is coming up. Bob Dunahugh
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320025 is a reply to message #320009] |
Wed, 05 July 2017 16:50 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Thermostat has nothing to do with how hot the engine gets. It only controls how cold it gets by throttling action at or below the set point. When pulling a grade a 160, 180 or 195 should all be wide open throttle and make no difference. The only advantage would be a lower temp at the start of the grade- which on a 11,000 lb vehicle is eradicated in the first 1/8 mile and means nothing in the big picture. There will be bigger temp swings with a lower temp stat like a160 (bad) when cooling conditions are good the engine will run at the stat which is too cold to be optimal. Then it will swing to the same high as the the unit running a 195. The overall capactiy of the system is what controls how hot it gets not the stat.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] What do those in the hot SW do for engine thermstats? [message #320030 is a reply to message #320009] |
Wed, 05 July 2017 18:47 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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I switched from a 195 to a 180 some time back. It might just be my imagination, but it seems like the fan clutch engages more with the 180 in there. Either way, the factory temp gauge (I know it is just a suggestion) stays rock steady at either temperature.
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
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| Re: [GMCnet] What do those in the hot SW do for engine thermostats? [message #320052 is a reply to message #320022] |
Thu, 06 July 2017 09:44 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Sure. But I don't suppose they run those cooling lines from the
transmission to the radiator in order to help cool the radiator.
Rick "thinking the engine needs to be hot enough to boil off condensate in
the oil, but not thinking it needs to be a lot hotter than that" Denney
On Wed, Jul 5, 2017 at 4:32 PM, Gary Kosier wrote:
> Rick,
>
> Don't forget the thermostat only controls the temperature in the engine.
> The efficiency of the radiator will control the temperature in the
> discharge
> tank where the tranny cooler is located. Before I lost my tranny pan temp
> sender, my pan temps were in the 130 degree range. That's a Cad 500
> with an aluminum radiator pulling a 4-door tracker here in the flatlands.
> No one, including me, has bothered to check the discharge temp of the
> aluminum radiator to know how good it really is. But I like it, yes I do.
>
> Gary Kosier
> 77PB w/500Cad
> Newark, Ohio
>
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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| Re: [GMCnet] What do those in the hot SW do for engine thermostats? [message #320053 is a reply to message #320052] |
Thu, 06 July 2017 10:07 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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On Thu, Jul 6, 2017 at 7:45 AM Richard Denney wrote:
> Sure. But I don't suppose they run those cooling lines from the
> transmission to the radiator in order to help cool the radiator.
>
> Rick "thinking the engine needs to be hot enough to boil off condensate in
> the oil, but not thinking it needs to be a lot hotter than that" Denney
>
> On Wed, Jul 5, 2017 at 4:32 PM, Gary Kosier
> wrote:
>
>> Rick,
>>
>> Don't forget the thermostat only controls the temperature in the engine.
>> The efficiency of the radiator will control the temperature in the
>> discharge
>> tank where the tranny cooler is located. Before I lost my tranny pan
> temp
>> sender, my pan temps were in the 130 degree range. That's a Cad 500
>> with an aluminum radiator pulling a 4-door tracker here in the flatlands.
>> No one, including me, has bothered to check the discharge temp of the
>> aluminum radiator to know how good it really is. But I like it, yes I
> do.
>>
>> Gary Kosier
>> 77PB w/500Cad
>> Newark, Ohio
>>
>>
>
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
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Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] What do those in the hot SW do for engine thermostats? [message #320060 is a reply to message #320052] |
Thu, 06 July 2017 13:44 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Tran cooler is cooling the oil from the torque converter that can reach 300
degrees . Pan temp is the fluid that is returned from the radiator.
On Thu, Jul 6, 2017 at 7:44 AM, Richard Denney wrote:
> Sure. But I don't suppose they run those cooling lines from the
> transmission to the radiator in order to help cool the radiator.
>
> Rick "thinking the engine needs to be hot enough to boil off condensate in
> the oil, but not thinking it needs to be a lot hotter than that" Denney
>
> On Wed, Jul 5, 2017 at 4:32 PM, Gary Kosier
> wrote:
>
>> Rick,
>>
>> Don't forget the thermostat only controls the temperature in the engine.
>> The efficiency of the radiator will control the temperature in the
>> discharge
>> tank where the tranny cooler is located. Before I lost my tranny pan
> temp
>> sender, my pan temps were in the 130 degree range. That's a Cad 500
>> with an aluminum radiator pulling a 4-door tracker here in the flatlands.
>> No one, including me, has bothered to check the discharge temp of the
>> aluminum radiator to know how good it really is. But I like it, yes I
> do.
>>
>> Gary Kosier
>> 77PB w/500Cad
>> Newark, Ohio
>>
>>
>
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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