| Radiator [message #285692] |
Mon, 24 August 2015 01:21  |
jturbo
Messages: 76
Registered: August 2013
Location: Socal
Karma: 1
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Looking at modern vehicle and different models of GMC's
Modern vehicles have the air baffled or forced through radiator sealed in sides and top bottom
What I have seen on GMC's
GMC Models made by GMC have radiator that is not baffled and air can sneak around the radiator
GMC models (Coachmen) these have some baffling to force the air through but you still have alot of blow around the radiator.
Has anyone investigated fixing this or building baffles to make the Stock Radiator work properly? or even improve the cooling?
1978 Royal 403
1977 Birchaven 455
1977 Kingsley 455
All under Upgrading and restoration
Rosemead California
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| Re: [GMCnet] Radiator [message #285697 is a reply to message #285692] |
Mon, 24 August 2015 01:28  |
Ronald Pottol
Messages: 505
Registered: September 2012
Location: Redwood City, California
Karma: -2
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People do it, it helps.
One thing to remember, modern cars are trying to do everything they can for
fuel efficiency, what is with it for an car company may not make any sense
to retrofit to these things.
On Aug 23, 2015 23:22, "john" wrote:
> Looking at modern vehicle and different models of GMC's
>
> Modern vehicles have the air baffled or forced through radiator sealed in
> sides and top bottom
>
>
> What I have seen on GMC's
>
>
> GMC Models made by GMC have radiator that is not baffled and air can sneak
> around the radiator
>
> GMC models (Coachmen) these have some baffling to force the air through
> but you still have alot of blow around the radiator.
>
> Has anyone investigated fixing this or building baffles to make the Stock
> Radiator work properly? or even improve the cooling?
>
>
>
>
> --
> 1978 Royal 403
> 1977 Birchaven 455
> 1977 Kingsley 455
>
> All under Upgrading and restoration
>
> Rosemead California
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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1973 26' GM outfitted
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| Re: [GMCnet] Radiator [message #285699 is a reply to message #285697] |
Mon, 24 August 2015 01:42 |
jturbo
Messages: 76
Registered: August 2013
Location: Socal
Karma: 1
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Point is also reliability of today's cars and what has made them that.
When I was little my parents drove across country all the time in Thunderbirds and Pontiac boneville's etc.
they always had coolant problems broken hose bad water pumpe never failed on a trip something always came up with the cooling system.
I'm looking to avoid that and by adapting updated tech to these vehicle I think it can be done.
1978 Royal 403
1977 Birchaven 455
1977 Kingsley 455
All under Upgrading and restoration
Rosemead California
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| Re: [GMCnet] Radiator [message #285702 is a reply to message #285699] |
Mon, 24 August 2015 02:30 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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jturbo wrote on Sun, 23 August 2015 23:42Point is also reliability of today's cars and what has made them that.
When I was little my parents drove across country all the time in Thunderbirds and Pontiac boneville's etc.
they always had coolant problems broken hose bad water pumpe never failed on a trip something always came up with the cooling system.
I'm looking to avoid that and by adapting updated tech to these vehicle I think it can be done.
Those with aluminum radiators seem to say their coach runs absolutely cool in all conditions. One thing with GMC is the temperature gauge out of the factory was notoriously wrong. There is a sender that makes it more realistic. Stock, when it gets to about mid range, it may be getting pretty hot. I have a real gauge on mine.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Radiator [message #285704 is a reply to message #285702] |
Mon, 24 August 2015 02:36 |
jturbo
Messages: 76
Registered: August 2013
Location: Socal
Karma: 1
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any idea what optimum operating temp is for the 455 and 403?
with addition of electric fans and other Items I'd like to see if temp can be managed better like a modern vehicle if possible?
1978 Royal 403
1977 Birchaven 455
1977 Kingsley 455
All under Upgrading and restoration
Rosemead California
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| Re: Radiator [message #285729 is a reply to message #285692] |
Mon, 24 August 2015 10:38 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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John,
The factory stock radiator and the aluminum replacement are both more than adequate to keep the engine cool- If the COMPLETE system( hoses, thermostat, belts, water pump, fan, fan clutch are kept in good working order.
I have driven several different coaches with stock cooling systems across country with absolutely no over heating issues.
I regularly drive my Palm Beach towing a 4000 lb Jeep the length of California (central valley is often +100F) and in the mountains of Nor Cal and Southern Oregon. The only heating issues I have ever had were the result of a failed fan clutch.
Maintained stock system will do the job. Armand's and other's modifications will make it more efficient. But if a pump, belt, hose, fan clutch, or thermostat fails you've got the same problem as your dad's Thunderbird.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: Radiator [message #285740 is a reply to message #285729] |
Mon, 24 August 2015 11:36 |
Jon payne
Messages: 495
Registered: May 2008
Karma: 1
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I installed the aluminum radiator as my original was worn out and not keeping the engine at a constant, cool temperature. Since installing the aluminum radiator the engine temp is pretty much rock steady not matter the OAT or the grade I'm climbling. Plus it is a brand new, not re-cored or reworked. If you want to make your cooling system reliable this should be on the top of your list.
Jon
Jon Payne
76 Palm Beach
Westfield,IN
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| Re: Radiator [message #285743 is a reply to message #285692] |
Mon, 24 August 2015 12:09 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Modello didn't understand the concept of a working thermostat.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Radiator [message #285745 is a reply to message #285692] |
Mon, 24 August 2015 12:11 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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And electric fans are a wimpy joke restricting airflow while pulling Amps we don't have to spare.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Radiator [message #285746 is a reply to message #285692] |
Mon, 24 August 2015 12:14 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Buy the under core support air deflector and you will sit on the stat point and never engage the fan unless pulling a long long grade at low road speed. Jim K and others sell them.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Radiator [message #285750 is a reply to message #285743] |
Mon, 24 August 2015 12:39 |
Jim Galbavy
Messages: 1443
Registered: August 2007
Karma: 7
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I wouldn't say that Joe Mondello didn't understand the concept of a working
thermostat. Most of Joe's applications were in 1/4 mile racers. Joe did
tell me to use a 195F thermostat in my 455 GMC. Totally different animals and
applications.
jim galbavy
'73 x-CL ANNIE
Lake Mary, FL
[Updated on: Mon, 24 August 2015 12:40] Report message to a moderator |
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| Re: Radiator [message #285776 is a reply to message #285692] |
Mon, 24 August 2015 19:24 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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I think his theory on the washer restrictor was more suited to the boat applications than our application. So he actually may be being misquoted.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Radiator [message #285783 is a reply to message #285692] |
Mon, 24 August 2015 20:49 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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For purely personal reasons, I opted to have a good shop recore my original radiator rather than replace it with a new one, aluminum or brass. The new core has more and larger flues. Last trip was on the freeway, 90 - 100 OAT, uphill and down, humidity over 85%. Digipanel pinned on the bar below 175 (engine has an original value thermostat, 160 degrees according to the stamp on it.) The stock system is adequate of as someone said it's in good order. It's gonna hafta take me and the Mousetoad over Monteagle in a few weeks, I have some trepidation about this. Basically, it's gonna be 'go or blow'.
--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
[Updated on: Mon, 24 August 2015 20:51] Report message to a moderator |
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| Re: Radiator [message #285795 is a reply to message #285729] |
Mon, 24 August 2015 22:56 |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
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gbarrow wrote on Mon, 24 August 2015 10:38
The factory stock radiator and the aluminum replacement are both more than adequate to keep the engine cool- If the COMPLETE system( hoses, thermostat, belts, water pump, fan, fan clutch are kept in good working order.
I completely agree...
Mondello put a restrictor in rather than nothing. The flow path needs the restriction of an open thermostat or equivalent to meter the flow correctly. Remember the water pump flow and radiator are sized with that flow rate in mind. The OE cooling system is more than adequate to keep a stock coach cool in the desert. This claim assumes a number of things that may or may not be true for most current owners;
1) the radiator is clean and unobstructed
2) the fan clutch works properly
3) the water pump has an impeller that moves the correct amount of coolant
4) the thermostat and other passages are not obstructed.
5) the axle ratio is stock
6) the engine is properly tuned
7) the coolant is less than 4 or 5 years old
 the engine power output has not been increased
9) you are not towing more than 1500 lbs.
If any of the above is false then you may have thermal issues. GMC recognized a few shortcomings and added a better fan shroud and baffles, but they validate these systems in the desert (the '73 vintage promo video was shot at the old Desert Proving Ground in Mesa, AZ).
I installed an aluminum radiator but I did it for the weight reduction not because it has any cooling advantage. I think some who have installed them make the assumption that the aluminum rad is better, when in fact any NEW radiator is better than what they had.
Also lots of misconceptions about thermostats...the stat does not control the peak temperature of the system, it controls the min temp when the system is at steady-state (ie a normal cruise on a mild day). The peak temperature is controlled by the radiator size, the coolant flow rate and the airflow through the radiator. If you increase the heat rejected to the rad, or restrict its ability to transfer heat by violating one of the nine items above you'll exceed the maximum design temperature of the system (typically about 235F)
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
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| Re: Radiator [message #285804 is a reply to message #285692] |
Tue, 25 August 2015 08:08 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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I had a sit down with the late Bob Drews where I told him of the occasional times that on hot days, traveling at highway speeds, or in town driving after a hot days run, that the engine temps would rise slowly to 208*, the fan would come on and quickly drag the temps back down to thermostate (192*). So, we know that the radiator could do the job, the the fan coming on proved it. It was obvious that not enough air was coming through the radiator at road or slow speeds on hot days. He took me over to my coach and showed me where all of the air can go once it gets through the grill. So maybe I had the side deflectors....not really sealed....How about over the top of the radiator? Or slip below the radiator? Around the deflectors....etc...etc. Lots of places for the air to go that is not through the radiator. The he took me to his coach where he showed me the "funnel" that he built out of conveyer belt material, around the radiator that confined in the air coming into the grill. Once the air got in and behind the grill, the only place it could go is through the radiator. On his advice, I then built a "funnel" out of conveyer belt material that I got at a farm supply. Since doing that, engine temps never exceed 200* and my thermo fan has never come on. Engine temps come up to thermostat and stay there. I took a set of pictures of it but everything behind the grill is black, so you cannot really see how the "funnel" is built. Come to GMCMI at Rapid City and I can show you.
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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