[GMCnet] what temp thermostat, 180 or 195?
Bruce Hislop
In the spring of 2009 I had the rad repaired and got a new thermostat from JimK. At the time he had only one listed on his site which turned out to be a 180* (80*C).
On the last couple of trips the water temp has been as low as 72C and as high as 92C according to the EBL Whats up display. The dash gauge which has its own sensor shows lower and higher as well so I don't think I have a sensor problem. Both used to read rock solid at 80C.
So it looks like a new thermostat is in the future. Which thermostat should I be using for a 77 with a 455? Is there any benefit to using the higher or preferably lower temp stat?
Thanks
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Armand Minnie
Your heater will work better with the 195 and I have been told that the 455 was designed to work at the higher temps.
--
Armand Minnie
Marana, AZ
'76 Eleganza II
TZE166V103202
http://www.minniebiz.com/gmcmotorhome
use the forum - it's easy
James Hupy
thermostat is to speed warm up of the coolant in the engine. It blocks
circulation until the specified temperature has been reached, and then opens
fully. At that point, it's job is more or less finished. Open is open. If
your temp is climbing and then falling, it sounds like perhaps it might be
time for a new Robert Shaw. They can be identified by the fact that they
have three support legs holding the temperature sensing element and are much
more durable than the two leg style. They come in various temp ranges, and
are sold by a number of different brands. Shop around, prices vary, but both
the Jim's have them in stock. I personally would not install any other style
in any engine I cared about. I always look for one additional feature and
that is that when they fail, they do so in the open position, not the closed
one. An engine will overheat very quickly when the thermostat is stuck in
the closed position. Hope this helps. Oh, by the way, my preference is 180
degree but there is nothing wrong with the 195 degree. The amount of heat
the engine is producing is the same either way.
Jim Hupy
Salem, OR
78 GMC Royale 403
Dan Gregg
Bruce, I run the 180 in summer and 195 in winter. I have no heat with the 180 so I always put the 195 in for winter. Opinions will vary. I also buy the fail open ones. I have had one fail closed, on my Mustang, and it will heat up very fast.
Dan
--
Dan & Teri Gregg
Soft White LED Lighting
http://danandteri.blogspot.com/
Jim Kanomata
180 will give you an edge when starting up hill as there is a greater
chance that it will be 180 at the base of the hill and will increase
by the time your up toward the top,
The difference can be 20 degrees. Add 20 to 180=200, add 20 to 195=215.
When the system runs cooler, we feel there is a chance that there
would be less stress applied to component parts by trying to keep the
temp lower.
I have been told by customers that our High flow Thermostats are the
correct Robert Shaw as it holds the seal when cold, not like the
others that are supplied and look identical.
This sounds like bull, but Steve Ferguson and others have blown on
them and made the statement.
I recall that Wes at Cinnabar printed a statement that he final drive
units can only accept a 3.42 ratio. We can put in 3.55 and 3.70 with
no modification. I make some statements and claims, but not that far
fetched.
--
Jim Kanomata
Applied/GMC, Fremont,CA
j...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
Rob Mueller
What Jim is talking about below is that Robertshaw makes "racing" thermostats that do note close all the way; they bypass flow no
matter what the engine water temp is.
I've Cc'd Gene Dotson on this email as I believe he can supply more info.
Regards,
Rob M.
-----Original Message-----
From: Jim Kanomata
I have been told by customers that our High flow Thermostats are the correct Robert Shaw as it holds the seal when cold, not like
the others that are supplied and look identical.
This sounds like bull, but Steve Ferguson and others have blown on them and made the statement.
Jim
fred veenschoten
James Hupy wrote on Sat, 22 October 2011 09:36
> Bruce, I will try to explain the difference. The real purpose of the
> thermostat is to speed warm up of the coolant in the engine. It blocks
> circulation until the specified temperature has been reached, and then opens
> fully. At that point, it's job is more or less finished. Open is open. If
> your temp is climbing and then falling, it sounds like perhaps it might be
> time for a new Robert Shaw. They can be identified by the fact that they
> have three support legs holding the temperature sensing element and are much
> more durable than the two leg style. They come in various temp ranges, and
> are sold by a number of different brands. Shop around, prices vary, but both
> the Jim's have them in stock. I personally would not install any other style
> in any engine I cared about. I always look for one additional feature and
> that is that when they fail, they do so in the open position, not the closed
> one. An engine will overheat very quickly when the thermostat is stuck in
> the closed position. Hope this helps. Oh, by the way, my preference is 180
> degree but there is nothing wrong with the 195 degree. The amount of heat
> the engine is producing is the same either way.
> Jim Hupy
> Salem, OR
> 78 GMC Royale 403
Jim, if i understand what you are saying the 180 will open at 180 and stay open but the 195 won't open till you reach 195 and then stay open. that tells me that, if the cooling system is OK, the engine will operate at 180 or 195 depending on which one you use. so, on a hot day pulling a toad up a long grade the engine will heat up no matter which one you use but it looks like the 180 will give you a head start on not overheating.
am i thinking right?
--
Fred V
'77 Royale RB 455
P'cola, Fl
Ken Henderson
But I agree with the logic of having the "15*F safety margin at the bottom
of the hill". So I wondered just how significant that benefit really is.
Y'All check the logic and mathematics of the following:
One British Thermal Unit [Btu] is the amount of heat required to raise the
temperature of 1 pound [ lb.] of water 1 degree Fahrenheit.
H20 weighs 8.33 pounds per gallon
GMCMH holds 21 qt. (call it 24 w/H20 heater) = 6 gal
6 * 8.33 = 49.98 lb ~=50 lb
1 hp = 42 Btu/min (look it up on the internet or calculate from 1 hp = 746
Watts & 1 Watt=3.412 Btu per hour)
Therefore 1 hp should raise 50 lb H20 by 42/50 = 0.84 degrees F per minute
Or 1 hp should raise the temperature by 15 degrees F in 15/0.84 = 17.9
minutes
Conversely, 17.9 hp would raise the temperature by 15 degrees F in one (1)
minute.
Since I'd expect the ascent of a grade steep enough to cause overheating
concern to require AT LEAST an additional 18 hp, after 1 minute my "15*F
safety margin" will be lost.
For that meager improvement, I'll retain the greater efficiency benefits of
the 195*F thermostat. Especially since, with my AL radiator, even the
Cad500, has no problem maintaining normal temperature.
JMHO,
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Sat, Oct 22, 2011 at 7:50 PM, fred veenschoten wrote:
>
> ...
> Jim, if i understand what you are saying the 180 will open at 180 and stay
> open but the 195 won't open till you reach 195 and then stay open. that
> tells me that, if the cooling system is OK, the engine will operate at 180
> or 195 depending on which one you use. so, on a hot day pulling a toad up a
> long grade the engine will heat up no matter which one you use but it looks
> like the 180 will give you a head start on not overheating.
> am i thinking right?
>
> --
>
Bruce Hislop
Can I disagree with this statement without being flamed?
"It blocks circulation until the specified temperature has been reached, and then opens fully. At that point, it's job is more or less finished. Open is open"
I'm not an engineer so please correct me if I'm wrong here... but I believe the thermostat will "modulate" the flow of coolant through it based on the temperature of the coolant around it. From stone cold it will be closed until until the coolant around it reaches its "rated" temperature, then it will start to open. At this time cold coolant from the rad will begin to flow into the engine and the engine will begin to warm this coolant as the hot coolant is being cooled by the rad.
If the coolant flows through too fast to heat it to the rated temp, the thermostat will begin to close and slow the flow rate through the engine until it reaches the rated temp around the thermostat. At that point the thermostat will begin to open more.
Of course if the coolant is above the rated temperature, it will stay wide open... but the cooling system must be designed to dissipate more heat than the maximum developed by the engine on the hottest summer day otherwise the roads would be filled with overheated engines.
Just my Farmboy mechanic way I see it anyway. Otherwise I can tell you there is no way a lightly loaded engine at -40C would ever stay warmed up!
I'm sure mine is just sticking.. open and it gets cooler (72C) then partially closed and it gets hotter (92C).
Ok, my rotten tomato shields are up.. go for it!
8)
Jim Kanomata
For me that concept works on a ambient temp up to 80degrees F.
After that I find that it does not really make much difference.
Also the theory of higher temp will dissipate heat more rapidly as the
difference in temp is greater.
All I can say is that the 195 seems to keep me warm on a cool day.
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
Rob Mueller
Did a Google search and came up with a couple of references:
http://auto.howstuffworks.com/question248.htm
http://en.wikipedia.org/wiki/Thermostat - Scroll down to Wax Pellet - Automotive
This paragraph supports your statement.
Regards,
Rob M.
-----Original Message-----
From: Bruce Hislop
Can I disagree with this statement without being flamed?
"It blocks circulation until the specified temperature has been reached, and then opens fully. At that point, it's job is more or
less finished. Open is open"
I'm not an engineer so please correct me if I'm wrong here... but I believe the thermostat will "modulate" the flow of coolant
through it based on the temperature of the coolant around it. From stone cold it will be closed until until the coolant around it
reaches its "rated" temperature, then it will start to open. At this time cold coolant from the rad will begin to flow into the
engine and the engine will begin to warm this coolant as the hot coolant is being cooled by the rad.
If the coolant flows through too fast to heat it to the rated temp, the thermostat will begin to close and slow the flow rate
through the engine until it reaches the rated temp around the thermostat. At that point the thermostat will begin to open more.
Of course if the coolant is above the rated temperature, it will stay wide open... but the cooling system must be designed to
dissipate more heat than the maximum developed by the engine on the hottest summer day otherwise the roads would be filled with
overheated engines.
Just my Farmboy mechanic way I see it anyway. Otherwise I can tell you there is no way a lightly loaded engine at -40C would ever
stay warmed up!
I'm sure mine is just sticking.. open and it gets cooler (72C) then partially closed and it gets hotter (92C).
Ok, my rotten tomato shields are up.. go for it!
8)
--
Bruce
_______________________________________________
Bruce Hart
up on the stove to be sure it would open, what I noticed was as it heated to
temperature the thermostat would slowly open up . If it is fully opened at
180 than would it start to open at 150, or 160. I didn't have a thermometer
at the time, I was just checking to see if it wold open and close.
Bruce Hart
Colorado
GMC wannabee
Ken Henderson
(probably in the others too): It specifies using a 33% glycol solution to
check for opening at 220*F and closing at 185*F (using a 195*F thermostat,
per spec, of course).
I read that 220*F full open spec as indicating that the cooling system
should have enough excess capacity for the thermostat to maintain the spec
195*F when PARTIALLY open.
By the way, photos there show how the thermostat should be oriented when
installed.
JWITIK,
Ken H.
On Sat, Oct 22, 2011 at 11:13 PM, Bruce Hart <hart...@gmail.com> wrote:
> As a shade tree mechanic, before I ever put in a thermostat I would heat it
> up on the stove to be sure it would open, what I noticed was as it heated
> to
> temperature the thermostat would slowly open up . If it is fully opened at
> 180 than would it start to open at 150, or 160. I didn't have a
> thermometer
> at the time, I was just checking to see if it wold open and close.
>
>
Ken Burton
Oh Boy, Here we go again. Colonel Ken is going to kill me.
I suggest you use a 180 degree thermostat. The thermostat REGULATES the coolant flow through engine to maintain the engine temperature. If does NOT stay open after reaching 180 degrees F. I tested my current GMC thermostat in a pan of hot water on the stove. The thermostat started to open at 180. It was FULL open at 187. As the water cooled down the thermostat started closing at 185 and was fully closed at 178. That is what is does as you are going down the road.
The reason 195 thermostats were introduced was an attempt to meet 1970's emission standards. The car manufacturers found they could run at 195 and not blow up an engine before the warranty ran out. After that they did not care. Supposedly a hotter running engine emits less crap into the air.
With the advent of engine computers and oxygen sensors and catalytic converters the need for 195 thermostats went away. My 2005 GM vehicle has a 180 degree thermostat in it and you can not even buy a 195 to fit it.
I suggest that running an engine cooler has many longevity advantages. Cooler oil is a better lubricant and lasts longer. I use 1 quart of oil every 6,000 miles. Cooler transmission fluid lasts longer. (the trans is bolted to the engine and runs at similar temperatures as the engine)
You do need to maintain a minimum oil temperature to boil away any accumulated moisture but that is not a problem because the oil is heated way above the boiling point when it traverses the cylinder walls but is immediately cooled down again as it mixes in the oil pan and traverses the oil cooler in the radiator before it is reused again.
In the mountains of West Virginia I blew a big hole in my 30 year old old radiator on the way to a rally in Delaware a few years back. I blocked and epoxied a couple of the tubes and continued on my way. I was concerned about how those blocked tubes would affect the engine temperature so I removed the thermostat and continued on my trip. For the rest of the trip to Delaware climbing up hill and going down I never reached 180 degrees so that diminished capacity radiator still had enough cooling capacity to do the job. The fan never turned on.
At the rally Colonel Ken, Emery Stora, and several others helped me install a new Aluminum radiator procured from Gene Dotson. I did not reinstall the thermostat until I reached home 850 miles later.
On the return trip I could not maintain 160 degrees running on 50% antifreeze. My point on all of this is the thermostat DOES MAINTAIN the running temperature of the engine (and trans).
Use a 180 thermostat. Your engine and trans will thank you.
Notes:
1. I also have external oil and trans coolers on my GMC.
2. Dick Paterson recommends using a 180 degree thermostat.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Matt Colie
Ken Henderson wrote on Sat, 22 October 2011 20:50
> First off, let me state that I'm an advocate of the OEM 195*F thermostat. But I agree with the logic of having the "15*F safety margin at the bottom of the hill". So I wondered just how significant that benefit really is. Y'All check the logic and mathematics of the following:
>
> One British Thermal Unit [Btu] is the amount of heat required to raise the temperature of 1 pound [ lb.] of water 1 degree Fahrenheit.
>
> H20 weighs 8.33 pounds per gallon
>
> GMCMH holds 21 qt. (call it 24 w/H20 heater) = 6 gal
> 6 * 8.33 = 49.98 lb ~=50 lb
>
> 1 hp = 42 Btu/min (look it up on the internet or calculate from 1 hp = 746 Watts & 1 Watt=3.412 Btu per hour)
>
> Therefore 1 hp should raise 50 lb H20 by 42/50 = 0.84 degrees F per minute Or 1 hp should raise the temperature by 15 degrees F in 15/0.84 = 17.9 minutes
>
> Conversely, 17.9 hp would raise the temperature by 15 degrees F in one (1) minute.
>
> Since I'd expect the ascent of a grade steep enough to cause overheating concern to require AT LEAST an additional 18 hp, after 1 minute my "15*F safety margin" will be lost.
>
> For that meager improvement, I'll retain the greater efficiency benefits of the 195*F thermostat. Especially since, with my AL radiator, even the Cad500, has no problem maintaining normal temperature.
>
> JMHO,
>
> Ken H.
Ken,
Logic is good (I haven't checked the math), but you left out the
fact that there is several hundred pounds of iron in the heat balance.
Maybe I'll come back to this when I am through playing in cold water.
Matt
--
Matt & Mary Colie
'73 Glacier 23 Chaumiere (say show-me-air) Just about as stock as you will find
SE Michigan - Twixt A2 and Detroit
Dan Gregg
As always, you guys are good. I have no dash heat with the 180 so I switch to the 195. Then, every summer I get to thinking about those hot days and the mountains out west, and put the 180 back. One of these days I will put the 195 in and just leave it. If everything is right it should do its job.
Thanks for the discussion,
Dan
--
Dan & Teri Gregg
Soft White LED Lighting
http://danandteri.blogspot.com/
Ken Henderson
>
>
> Oh Boy, Here we go again. Colonel Ken is going to kill me.
>
>
Not hardly. If you want to destroy your engine the next time you crank it
up, that's fine by me. :-)
I'd rather get in a tire war than this one, despite Carnot.
I just wanted to see how much "hil climbing" benefit I could expect from a
lower temperature thermostat -- not much. And the absence of a clear winner
in the war indicates that it doesn't much matter longer term either.
Ken H.
Rob Mueller
This doesn’t make sense! Are you saying the heater does not blow hot air if you have a 180° thermostat installed you have to have a
195° thermostat installed?
If everything is right you should get heat with a 180° thermostat installed.
I suspect the water flow rate through your dash heater may be restricted.
I'd check and see if the shutoff valve opens fully and if it does I'd disconnect the inlet and outlet hoses from the heater core and
try back flushing it with a garden hose.
Regards,
Rob M.
-----Original Message-----
From: Dan Gregg
As always, you guys are good. I have no dash heat with the 180 so I switch to the 195. Then, every summer I get to thinking about
those hot days and the mountains out west, and put the 180 back. One of these days I will put the 195 in and just leave it. If
everything is right it should do its job.
Thanks for the discussion,
Dan
_______________________________________________
Phil Swanson
Even more important than the temperature is the TYPE thermostat to run. Robert Shaw used to make the best ones that allow for max volume of water to pass thru in the open position. Do not run the cheap ones you find locally. Summit and others still sell HP ones based on the old RS design. I prefer the 180 in a warm climate and would run a hotter one in very cold weather but the type is far more important.
Phil Swanson
r...@gmcnet.org
The difference I found between the 2 thermostats was the clutch fan came on less when using the 195 thermostat. Now that I have an Aluminum radiator and a clutch fan that likes to hardly come on at all I use the 180 thermostat.
Roy
Jim Kanomata
Can you do quick comparison of heat transfer of 180/195 to a ambient
temp of around 90degrees?
You can see that what I learned in Thermodynamic course has long been forgotten.
I have heard from many people that the 195 has decreasd the fan from
engaging so frequently.
When we use to Drag race, we would use 165 thinking it will keep the
engine cooler and get little mor power at the line as the temperature
would run high.
Ken Henderson
I'm sure my thermodynamics is even more rusty than yours -- and probably
less extensive; I was, after all, mostly a EE student. :-)
More importantly, I'm not sure what you want to calculate for 180*F/195*F
down to 90*F -- Btu/min? At what horsepower? And what are the heat
transfer coefficients for the cooling system, etc., etc. In other words, I
have no idea where to start. :-(
But I do suspect your drag racing plan with the low temperature thermostat
was counter-productive: The Carnot cycle dictates that engine efficiency
increases as the differential temperature increases; i.e., you want delta-T
from the engine to ambient as high as possible (delta-T being on the Kelvin
scale means 190*F-165*F ain't much, percentage-wise). But then that was all
derived from steam engines, so who cares? :-)
Ken H.
James Hupy
seem to recall something about the correlation between the rate of flame
propagation and the temperature of the container/cylinder. Something like
for every 10 degrees of farenheit higher the speed of the reaction is
doubled until it can no longer be controlled; ie, preignition and or
detonation are uncontrolled events. I really do not know the difference in
the temperature of the combustion chamber between a 180 or a 195 degree
thermostat, but personal experience with a BB Chrysler Wedge motor when the
reformulated gas first arrived on the scene. I wound up re camming and
milling the tops of the pistons, and lowering the thermostat from 195 to 180
to be able to run the new wonderfuels. I reduced the compression from 10.5
to 1 down to 8.0 to 1. Turned that great engine into a mediocre one that
didn't spark knock. I guess that what I am saying is that I don't see a
great deal of difference in an Olds engine in a GMC with either thermostat.
When we run the 455 in a boat with sea water cooling, we sometimes restrict
the discharge cooling water to keep the water in the engine long enough to
absorb heat at a rate that allows the engine temperature to stabilize. If
you don't restrict the flow, the engine never runs hot enough to carburate
correctly. Seat of the pants stuff, no formulae involved.
Jim Hupy
Salem, OR
78 GMC Royale 403
Rob Mueller
As I mentioned earlier when the ambient temperatures are cool the H2O temp in Double Trouble does not reach 180°. I suspect this is
due to the amount of flow through the thermostat bypass and the aluminum radiator.
Should I consider restricting the flow through the thermostat bypass until the amount of flow is reduced enough to get the engine to
run at 180° minimum no matter what the ambient conditions.
Regards,
Rob M.
r...@gmcnet.org
Jim
Why did you bring up Thermodynamics I had the course 3 different times and I never did get it.
Roy
Steve Southworth
roy1 wrote on Sun, 23 October 2011 18:36
> Jim
> Why did you bring up Thermodynamics I had the course 3 different times and I never did get it.
> Roy
Thermo was OK. Final exam was to design a steam power plant (simplified). It was Linear Systems/Differential Equations that put my plans for an engineering degree in the dumpster. Took it 4 times at two different schools, never could get it enough to pass it.
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
James Hupy
math which was my worst subject. I thought at the time "I will never use
this crap", boy was I wrong. I struggled through and applied my self and got
fair grades in spite of my disdain for the subject. Kinda like english and
sentence structure, use it all the time but I have yet to diagram a
sentence.<Grin>
Jim Hupy
Salem, OR
78 GMC Royale 403
Richard Denney
> First off, let me state that I'm an advocate of the OEM 195*F thermostat.
> But I agree with the logic of having the "15*F safety margin at the bottom
> of the hill". So I wondered just how significant that benefit really is.
> Y'All check the logic and mathematics of the following:
>
Let me add empirical evidence:
At the base of the hills on I-81 between Harrisonburg and Winchester, VA,
which I drive in the coach once or twice a year, my engine temperature,
measured with a good mechanical gauge, ranges from 180 to 200. It works its
way up from 180 to 200, the fan clutch engages, and then it drops like a
stone back to 180. It takes maybe 15 minutes on the way up, and less than a
minute on the way down.
When I cross the Shenendoah River, the next thing is a steep 8% climb up the
side of the Blue Ridge. On a hot day, with the AC running, the temp will
rise from 180 to perhaps 205 or 210. The rise is much faster because of the
climb--maybe three or four minutes. I think it gets to a hotter temperature
only because it takes longer for the heat made by the engine to work its way
to the air surrounding the fan clutch. But when the fan engages, the
temperature drops back down to 180 quickly, even during a climb. That's the
only climb on that route that is steep and long enough to cause the clutch
to engage during the climb. Most of the time, it engages after cresting the
hill.
I also have an aluminum radiator, and my cooling system, after much effort
to make it so, is tip-top as far as I know.
I'm thinking that I am making use of that margin. And I'm also wondering if
a 195-degree thermostat would do battle with my fan clutch because of a lack
of a hysteresis loop. I have a fan clutch that I know works, and that's
worth working with.
Rick "not thinking 15 degrees will affect efficiency all that much" Denney
--
'73 230 "Jaws"
Northern Virginia
Ken Burton
Ken Henderson wrote on Sun, 23 October 2011 09:11
> On Sun, Oct 23, 2011 at 3:56 AM, Ken Burton <n9...@comcast.net> wrote:
>
> >
> >
> > Oh Boy, Here we go again. Colonel Ken is going to kill me.
> >
> >
> Not hardly. If you want to destroy your engine the next time you crank it
> up, that's fine by me. :)
>
> I'd rather get in a tire war than this one, despite Carnot.
>
> I just wanted to see how much "hil climbing" benefit I could expect from a
> lower temperature thermostat -- not much. And the absence of a clear winner
> in the war indicates that it doesn't much matter longer term either.
>
> Ken H.
I doubt there is much benefit on climbing hills. Once you generate more heat than the cooling system can dissipate, the temperature is going to rise rapidly. At that point you have to rely on the fan clutch and fan to remove the excess heat you are generating.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Larry
I have struggled with a perceived overheating problem for the last 4 years. On the road at a steady 60-65 mph, if ambient temps were over 80* F, my coolant temp would slowly rise to 210. At that point the fan clutch would come on and drag the temp down to 192 (Thermostat temp) pretty quickly. judging from the speed that the temp came down, I knew that the aluminum radiator was working and felt that at hwy speed I was just not getting enough air through the radiator. When the fan clutch engaged, it forced enough air through to do the job. On a suggestion from Bob Drews, I went to a farm supply outlet (go figure) and bought 8 feet of heavy rubber conveyer belt material. I used it to make a funnel from the radiator to the grill, completely sealing the grill area such that air coming in the grill cannot escape up over, around the sides, or under the radiator. Once the air gets in the grill, the ONLY place it can go is through the radiator. I put it to the test going to th
e Goshen rally this fall. We drove in 98* weather towing a car with the AC on. The only time the temp ran above 200* was when we slowed down for small towns. The fan clutch came on only two times...both in slow traffic situations.
Some coaches...for what ever reasons...simply do not have enough air flow (through) the radiator. Try building a funnel...it worked for me.
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.
Dan Gregg
Larry wrote on Mon, 24 October 2011 08:02
> I have struggled with a perceived overheating problem for the last 4 years. On the road at a steady 60-65 mph, if ambient temps were over 80* F, my coolant temp would slowly rise to 210. At that point the fan clutch would come on and drag the temp down to 192 (Thermostat temp) pretty quickly. judging from the speed that the temp came down, I knew that the aluminum radiator was working and felt that at hwy speed I was just not getting enough air through the radiator. When the fan clutch engaged, it forced enough air through to do the job. On a suggestion from Bob Drews, I went to a farm supply outlet (go figure) and bought 8 feet of heavy rubber conveyer belt material. I used it to make a funnel from the radiator to the grill, completely sealing the grill area such that air coming in the grill cannot escape up over, around the sides, or under the radiator. Once the air gets in the grill, the ONLY place it can go is through the radiator. I put it to the test going to
the Goshen rally this fall. We drove in 98* weather towing a car with the AC on. The only time the temp ran above 200* was when we slowed down for small towns. The fan clutch came on only two times...both in slow traffic situations.
>
> Some coaches...for what ever reasons...simply do not have enough air flow (through) the radiator. Try building a funnel...it worked for me.
Good information Larry. When Bob D. speaks it is good to pay attention. I have seen others do this. I have never had an over heating problem but this last fan clutch wants to "work" a lot. So, I installed the side flaps, 1974 model did not have them, and John Wright's air scoop. That seems to have really helped the fan clutch but that lower scoop is a pain in the butt. Can't get in and out of my drive without dragging it. So, I think I saw on Jim K's site the "funnel" parts. I may order the top and bottom pieces and do as you have done. Maybe I can then eliminate the lower scoop.
Thanks for sharing your solution.
Dan
--
Dan & Teri Gregg
Soft White LED Lighting
http://danandteri.blogspot.com/
Larry
WD0AFQ wrote on Mon, 24 October 2011 10:23
> Good information Larry. When Bob D. speaks it is good to pay attention. I have seen others do this. I have never had an over heating problem but this last fan clutch wants to "work" a lot. So, I installed the side flaps, 1974 model did not have them, and John Wright's air scoop. That seems to have really helped the fan clutch but that lower scoop is a pain in the butt. Can't get in and out of my drive without dragging it. So, I think I saw on Jim K's site the "funnel" parts. I may order the top and bottom pieces and do as you have done. Maybe I can then eliminate the lower scoop.
> Thanks for sharing your solution.
> Dan
Dan,
I had the same concern about the lower scoop. So, I just bent the brackets so that it did not hang down as far. Seems to work and does not drag. JWID
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.