Home » Public Forums » GMCnet » Heat Concerns (Desert travel)
| Heat Concerns [message #284856] |
Fri, 14 August 2015 09:51  |
misnomer
Messages: 40
Registered: April 2015
Location: Reno
Karma: 1
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Those of you who live in the desert, have you had any concerns with heat? My cooling system is in good working order and the prior owner installed engine bay air vents. My concern is an upcoming trip that might involve several hours of low speed quite possibly in 100 degree heat and would like to run ACs (roof or dash or both?).
So, desert rats - any common issues with the original setup? Any recommendations for additional fans or other cooling for either the engine bay or the Onan? I've gathered it's better to keep the clutch fan and shroud in place and not obstruct the front with any pusher fans.
Anyhow, if I'm over thinking it and these guys do great in the heat, wonderful! Thanks for the help!
~John
77 Birchaven 23 w/ 455
Reno, NV
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| Re: [GMCnet] Heat Concerns [message #284867 is a reply to message #284856] |
Fri, 14 August 2015 10:52  |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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John,
It would be very helpful if in your Signature line you would include the year and model of your coach and possibly the state in which you reside. We need the year and model to determine which type of AC you have, but mostly the year.
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCGL Tech Editor
GMCMHI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan
> On Aug 14, 2015, at 10:51 AM, John Yurtinus wrote:
>
> Those of you who live in the desert, have you had any concerns with heat? My cooling system is in good working order and the prior owner installed
> engine bay air vents. My concern is an upcoming trip that might involve several hours of low speed quite possibly in 100 degree heat and would like to
> run ACs (roof or dash or both?).
>
> So, desert rats - any common issues with the original setup? Any recommendations for additional fans or other cooling for either the engine bay or the
> Onan? I've gathered it's better to keep the clutch fan and shroud in place and not obstruct the front with any pusher fans.
>
> Anyhow, if I'm over thinking it and these guys do great in the heat, wonderful! Thanks for the help!
> ~John
>
> _______________________________________________
> GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: Heat Concerns [message #284869 is a reply to message #284856] |
Fri, 14 August 2015 11:15 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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As JR suggests you should display the year and size of your coach. The dash air can be improved on some years to cool a lot better. I live about 45 minutes south of you. The climb to Lake Tahoe is a bit steep as well as 395 south to souther cal for sure. I do it with a toad but I have 3.70 differential gears. A good water temp gage is important as well as a functioning clutch fan . Also a good radiator is important.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: Heat Concerns [message #284870 is a reply to message #284869] |
Fri, 14 August 2015 11:23 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Suggest, if you run the overhead air, do not run the dash air. This may help the heat accumulation in the engine compartment.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Heat Concerns [message #284875 is a reply to message #284856] |
Fri, 14 August 2015 11:41 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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John, I drive my '78 Royale in similar heat regularly. I find that the dash A/C is adequate to keep the front seats cool enough even in serious (!) heat, though if the coach has been sitting outside in 110 degree sunshine, it's gonna take a LONG time to get it really "comfortable". And if you have passengers in the "house", you're going to have to run the rooftop A/C to keep them from staging a mutiny.
My PO installed engine vents, and I can only guess they help - I've never seen the temperature gauge climb above about 1/4 (which is where it's supposed to be with a stock sending unit). He also cut some NACA vents into the generator compartment door, which presumably help move air through - I know I've successfully run my Onan 6.5kw Emerald Plus generator for hours in serious heat without any problems. The other mod my beloved PO put in was a supplemental electric fuel pump. I did have some serious vapor lock only once, when I was in stop-and-go traffic at around 115 degrees. Hit the switch for the pump and "vroooooom"... back to 100%.
So yes, I'd say you should generally have no problems with the heat in Reno, though it might still be a good thing to hear from others with your generator set-up just to make certain there's not a big difference in the way a 23' coach moves air through the generator compartment.
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: Heat Concerns [message #284882 is a reply to message #284876] |
Fri, 14 August 2015 13:15 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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The dash air in my '75 is not really adequate for cooling in the cockpit area, it should be MUCH better in your '77 (so I've heard). One trick is to hang a clear plastic curtain between the cockpit and the living area to retain the AC in the front. If you have passengers in the back, run the Onan and the roof air. If your cooling system is in good condition, you should not have any issues with overheating the engine. Having a working fan clutch is very important for slow driving in the Summer. Just make sure all your belts and hoses are in good shape, and your radiator is clean.
An electric fuel pump is almost essential with the current gasoline formulations. I installed mine between the aux. tank and the selector valve and run it off of the selector valve wire. That way, whenever I need it, I simply switch the tank to Aux, and it comes on. This wiring method does not provide the the safety feature of an oil pressure shut down switch, which some feel is necessary. Also, change any and all fuel filters before you go. A dirty filter will cause you additional problems in an already heat stressed fuel delivery system.
A while back, my wife found these cooling towels that are available in different sizes and brands. You get the towel wet, wring out the excess moisture, shake it out like you would a rug, and drape it over your head or around your neck. They work like an evaporative cooler and do an amazing job of keeping you cool. We also use them for hiking.
http://www.amazon.com/ArcticBlu-Instant-Cooling-Towel-Green/dp/B00U0LFBR6/ref=sr_1_51?ie=UTF8&qid=1439576056&sr=8-51&keywords=cooling+towe ls
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] Heat Concerns [message #284888 is a reply to message #284882] |
Fri, 14 August 2015 14:36 |
Margie Van Winkle
Messages: 51
Registered: March 2012
Karma: 0
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If you still have the curtains behind the drivers/passenger seats use them
to keep that cool dash air up front. That is IF you don't have passengers
in the back. Works for us both summer and winter.
On Aug 14, 2015 1:15 PM, "Carl Stouffer" wrote:
> The dash air in my '75 is not really adequate for cooling in the cockpit
> area, it should be MUCH better in your '77 (so I've heard). One trick is to
> hang a clear plastic curtain between the cockpit and the living area to
> retain the AC in the front. If you have passengers in the back, run the
> Onan
> and the roof air. If your cooling system is in good condition, you should
> not have any issues with overheating the engine. Having a working fan
> clutch is very important for slow driving in the Summer. Just make sure
> all your belts and hoses are in good shape, and your radiator is clean.
>
> An electric fuel pump is almost essential with the current gasoline
> formulations. I installed mine between the aux. tank and the selector
> valve and
> run it off of the selector valve wire. That way, whenever I need it, I
> simply switch the tank to Aux, and it comes on. This wiring method does not
> provide the the safety feature of an oil pressure shut down switch, which
> some feel is necessary. Also, change any and all fuel filters before you
> go. A dirty filter will cause you additional problems in an already heat
> stressed fuel delivery system.
>
> A while back, my wife found these cooling towels that are available in
> different sizes and brands. You get the towel wet, wring out the excess
> moisture, shake it out like you would a rug, and drape it over your head
> or around your neck. They work like an evaporative cooler and do an amazing
> job of keeping you cool. We also use them for hiking.
>
>
> http://www.amazon.com/ArcticBlu-Instant-Cooling-Towel-Green/dp/B00U0LFBR6/ref=sr_1_51?ie=UTF8&qid=1439576056&sr=8-51&keywords=cooling+towe ls
> --
> Carl Stouffer
> '75 ex Palm Beach
> Tucson, AZ.
>
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| Re: Heat Concerns [message #284895 is a reply to message #284856] |
Fri, 14 August 2015 16:03 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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misnomer wrote on Fri, 14 August 2015 07:51Those of you who live in the desert, have you had any concerns with heat? My cooling system is in good working order and the prior owner installed engine bay air vents. My concern is an upcoming trip that might involve several hours of low speed quite possibly in 100 degree heat and would like to run ACs (roof or dash or both?).
~John
John,
You have good answers here and seem to be looking into preventive actions. The thing that concerns me is the line about low speed. I have vents in the sides of the engine compartment but our coach tends to get warmer when in stop and go. Above 30 is much better. The engine speed is up a bit and the fan working better.
The slow going can also drive up transmission temperature as the torque converter is doing a lot of slipping. All that heat goes to the radiator as well, unless you have an external transmission cooler.
I do have an auxiliary transmission cooler but it has no fan so it is pretty useless when I am not moving. Last time I was in a California highway 99 stop and go situation I had Ruth start the generator for roof air as the engine temp just kept climbing. I have, since then, changed the fan clutch (again). That silly thing never engaged correctly.
If you still have a carburetor a good fan clutch will help when slow moving if you put it in neutral now and then and run it up to say 1800 or so, so that air is blowing over the carb as well. It will be blowing hot air but when going slow the fuel in the bowl is not being changed out very fast and may get to hot and cause starvation. If you have an add-on heat gauge you will see the temperature drop quickly when you run up the RPMs a bit.
If you have an original heat gauge and sender 1/2 needle is getting pretty warm.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Heat Concerns [message #284923 is a reply to message #284856] |
Fri, 14 August 2015 19:51 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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GM tested them in the desert and after that added another blade to the fan before they signed off on the cooling system. In the big picture running the dash air puts only minimal additional cooling/ engine load on the system compared to how much air the fan can move when needed. Also the condenser covers less than half the radiator area. At about 10 years radiators should be replaced or seviced at an old school radiator shop. My coach runs coolest at low to moderate speeds. Never climbs in traffic It's over 65 all that fuel burn to fight air to push the coach through (road load) or long upgrades that really tax the cooling system. But after a slight climb on the gauge you should hear the fan engage and rapiidly keep temps in check.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Heat Concerns [message #284935 is a reply to message #284856] |
Fri, 14 August 2015 22:18 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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misnomer wrote on Fri, 14 August 2015 08:51Those of you who live in the desert, have you had any concerns with heat? My cooling system is in good working order and the prior owner installed engine bay air vents. My concern is an upcoming trip that might involve several hours of low speed quite possibly in 100 degree heat and would like to run ACs (roof or dash or both?).
So, desert rats - any common issues with the original setup? Any recommendations for additional fans or other cooling for either the engine bay or the Onan? I've gathered it's better to keep the clutch fan and shroud in place and not obstruct the front with any pusher fans.
Anyhow, if I'm over thinking it and these guys do great in the heat, wonderful! Thanks for the help!
~John
I regularly use my coach in hot 110 temps and a few things are mandatory--a good fan clutch and a clean radiator--both internally and outside (bugs, etc.)Make sure you don't have leaves stuck between the AC condenser and the radiator. Since your fan clutch will hopefully engage quite often, make sure your drive belts are tight and in good shape. I use an electric booster fuel pump that I run only when necessary--high altitude and when sitting at lights or slow driving in town. I don't have engine compartment vents. My 78 style AC with Duracool does a fine job. Although my original Onan is gone, it ran fine on the road with no modifications. Make sure your tire pressures are up to at least 65 front and rear. If you are climbing steep grades, keep the RPM's up rather than let it lug. As far as non ethanol fuel in this area, forget it. I also noticed that keeping speeds below 75 help keep the temps down a lot.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Heat Concerns [message #284954 is a reply to message #284856] |
Sat, 15 August 2015 07:57 |
winter
Messages: 247
Registered: September 2007
Location: MPLS MN
Karma: 0
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Senior Member |
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Would a shutoff valve on the line to the heater core help?
Jerrod Winter
1977 Palm Beach
Green Jelly Bean
Twin Cities, Minnesota
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| Re: Heat Concerns [message #284957 is a reply to message #284856] |
Sat, 15 August 2015 08:19 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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It might help heat in the coach. However, it would deny the last resort for engine overheating, which is to turn the heater on high and sweat.
--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: Heat Concerns [message #284959 is a reply to message #284856] |
Sat, 15 August 2015 08:34 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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And obviously fresh E G antifreeze at 50/50 mix. Going more concentrated raises boiling point a bit but reduces heat transfer efficiency so don't recommend that.
John Lebetski
Woodstock, IL
77 Eleganza II
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