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
What do those in the hot SW do for engine thermstats?
- Thread starter Bob Dunahugh
- Start date
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.
> 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
>
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.
> 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
>
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
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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
--
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" - ol Andy, paraphrased
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
--
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" - ol Andy, paraphrased
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.
>
>
>
> > 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
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.
>
>
>
> > 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
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.
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.
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
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
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
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
I need to get a 195 tomorrow. As I THINK I have a dyeing thermostat. And I need to confirm my Digi Panel readings. As the readings are taken at the hottest coolant area of the engine. And it might be interesting to check the temps on the right side of the radiator that the trans cooler is located. This would be interesting to see the temp of the coolant that's going back to the water pump. Plus, I'd like to see how much the radiator trans cooler drops the trans fluid temps. Then check the aux trans cooler as the fluid goes back to the trans. ( Seen many an aux trans cooler put on the wrong line ) Going to Duluth Sat. I'll get the temps then. And post that info. Getting more people to check these numbers. Just might help diagnose others issues. Plus we might have to make charts that cover 73 - 76. Then different data charts for just 77-78. That just might be even more interesting data. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Wednesday, July 5, 2017 12:26 PM
To: gmclist
Subject: What do those in the hot SW do for engine thermstats?
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
________________________________
From: Bob Dunahugh
Sent: Wednesday, July 5, 2017 12:26 PM
To: gmclist
Subject: What do those in the hot SW do for engine thermstats?
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
My last DigiPanel had the trans temp sensor on the return line from the cooler. It tracked the radiator temp.
==johnny
--
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" - ol Andy, paraphrased
==johnny
--
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" - ol Andy, paraphrased
