wolfe10
Texas
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Joined: 10/08/2000
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Jim-- sorry, don't mean to throw stones, but many owners/potential owner may not have as clear an understanding of the air flow and whre the debris is deposited. Cleaning the radiator has lead MANY to the wrong conclusion as to where the dirt is deposited. I know-- I give the Caterpillar RV Engine Maintenance Seminars at the FMCA Conventions and that question comes up virtually everytime.
Just wanted to make it clear that the vast majority of the dirt is not deposited on the radiator (which is accessibly from the back).
Instead, it is on the front of the CAC, which acts as a "filter" to catch most of the debris before it gets to the radiator.
Air flows from under the motorhome, where 35'+ of motorhome and 6 tires traveling at highway speeds stirs up a lot of dirt. That air then passes over the hot rear axle, hot transmission and hot engine (any of which could introduce a little oil/oil vapor) before the fan sucks it up and pushes it into the CAC and behind that the radiator.
Brett Wolfe
1993 Foretravel 36' U-240
Cat 3116, Allison 3060
FMCA Forum: www.community.fmca.com/index
Caterpillar RV Engine Owner's Club: www.catrvclub.org
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pusherpilot
Wherever we are.
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Joined: 03/13/2006
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We had a 2000 Safari Zanzibar 38ft 3126b Cat, Alison 3060, rear radiator. The entire product line was plagued with overheating problems. It was exacerbated by increasing the hp output of the engine without significantly increasing the radiator capacity or the designed cooling capacity of the system. We had a couple of incidents of warning chimes and were forced to stop and cool it down. This happened only on long up hills or short steep grades. Typically we'd have to stop twice going over the passes from Shasta Ca to Eugene Or. No am0unt of slowing and dropping down gears etc helped. Safari issued a "heat kit" which consisted of a new fan shroud, rear doors with bigger slots, a rear bumper grill, a new fan with two more blades, and a pulley change to increase the RPMs of the fan. They installed this at no cost and it seemed to work. The temp would get up there but we didn't have to stop again for the rest of the time we had the coach.
We now have a 04 HR Imperial ISL 400 with side radiator. We have never had an incident of elevated heating above 280-290 degrees.
I've seen the newer coaches with the ISL and rear radiators and marvel at the size of the radiators!! They seem to work but personally I'll stick with the side arrangement, I like being able to get into that area without crawling around on the ground or trying to wriggle in from the trap doors in the bedroom.
The only thing I don't like about the side radiator is that when we drive into a CG or down a dirt road the thing kicks up so much dust you literally can't see behind the coach. The side config draws air in the side and blown it out the bottom. When leaving a CG I try to get moving before the fan kicks into high mode so I don't upset too many folks. Coming into the parks is another matter altogether!!
Ron
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jauguston
Bellingham, WA
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Joined: 07/03/2005
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Ron,
You did mean 180°-190° didn't you (-:
I just went through the unpleasant task of accessing my C-7 from the top to check my CAC and radiator as well as connect my MP-8 programmer. I just bought this coach and it has 28,000 miles on it and a extended slobber tube. I was very pleased to see the CAC and radiator were clean. The CAC is not as tall as the radiator. I can see the radiator over the top of the CAC.
My C-7 runs at 200° uphill and down. It will be interesting to see if the temperatures go up pulling long hills with the MP-8 turned up.
Jim
* This post was
edited 09/02/10 04:49pm by jauguston *
2005 Coachman Sportscoach Elite 402 40'
350hp Cat C-7 w/MP-8
7500w Onan quiet diesel generator
6-Kyocera 130w solar panels SB3024i MPPT controller
Pressure Pro TPMS
1987 Suzuki Samurai tintop Toad w/VW 1.6 turbo diesel power
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adondo
Pasco, Washington
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Joined: 07/28/2004
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Brett does make a good point. Both side and rear radiators are NOT just radiators. They're a STACK of radiator/coolers, the actual engine's radiator being only one of the stack.
They are generally:
A) The CAC (Charge Air Cooler) or intercooler, take your pick of terms.
B) Engine oil cooler
C) Transmission fluid cooler
D) Hydraulic system cooler
E) Engine coolant radiator
And, maybe F) dash air-conditioner condenser. Most are mounted up front with a separate electric fan, but some may be part of the radiator stack depending on the coach build. If it's a FRED, then the A/C condenser may well be the head of the stack, and certainly are in gasser rigs.
At any rate, the engine coolant radiator is just about always the bottom (last unit) of the stack.
As for dusty roads, the rear radiator air stream is straight back, so no extra dust lifting there. The dust problem is getting it kicked up by the tires etc. and getting the dust blown thru the radiator stack, where it can collect.
FMCA# F355513. 40 foot Safari Continental, one slide, Cat powered Magnum Blue Max chassis, PAC brake PRXB, Allison MD3060, Aqua-Hot, 7.5 KW Quiet Diesel, Howard PCS, Velvet Ride suspension. 2006 Jeep Commander.
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Bigdog
silverdale wa.
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Joined: 06/28/2002
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A couple of other dust raisers are your genny exhaust,especially when you go thru a cg with gravel or dirt roads and the A/Cs running and the exhust pipe from your main engine. Man,but those diesels do put out a large volume of air under pressure..
GO COUGARS
2001 Tradewinds 7390 LTC
330 Cat Turbo Freightliner Chassis
2004 Chevy Trailblazer LS (toad)
'88 Mustang 5 Spd 5.0L GT convertible (not Toad)
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B Bob
USA
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Joined: 05/07/2003
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If at all possible you want a side radiator. The only advantage to a rear one is the cost is lower.
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