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Old 04-11-2013, 05:33 PM   #1
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Radiator Fan Trouble

I bought a 2009 390BH Berkshire in May 2011 with 12500 miles. Recently at about 31600 miles, I experienced a sudden engine overheat. Long story short, radiator hub had detached from back face of engine and fan tilted and seized in shroud. Three of four bolts holding hub to engine had broken and the fourth had backed out about 2mm. Repair required removal of radiator and removal of broken bolts. Fifth hole drilled and tapped to improve strength of hub to engine interface by ATC Freightliner techs in OKC. They also commented they'd seen several of these types of repairs because original bolts are of inadequate strength and penetrate engine block only about 12mm. Radiator hub is a Freightliner add-on to the Cummins 360 engine before coach ready chassis delivery to Forest River. Has anyone else seen this problem? Is there a DOT recall or tech advisory from Freightliner, Cummins or Forest River? I was fortunate that the fan didn't disintegrate and damage the radiator, but my fan still had to be replaced because of sudden-stoppage fractures. Cost of repair almost $2400. Any enlightenment welcomed.
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Old 04-11-2013, 06:20 PM   #2
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I bought a 2009 390BH Berkshire in May 2011 with 12500 miles. Recently at about 31600 miles, I experienced a sudden engine overheat. Long story short, radiator hub had detached from back face of engine and fan tilted and seized in shroud. Three of four bolts holding hub to engine had broken and the fourth had backed out about 2mm. Repair required removal of radiator and removal of broken bolts. Fifth hole drilled and tapped to improve strength of hub to engine interface by ATC Freightliner techs in OKC. They also commented they'd seen several of these types of repairs because original bolts are of inadequate strength and penetrate engine block only about 12mm. Radiator hub is a Freightliner add-on to the Cummins 360 engine before coach ready chassis delivery to Forest River. Has anyone else seen this problem? Is there a DOT recall or tech advisory from Freightliner, Cummins or Forest River? I was fortunate that the fan didn't disintegrate and damage the radiator, but my fan still had to be replaced because of sudden-stoppage fractures. Cost of repair almost $2400. Any enlightenment welcomed.
Luckily, that is not one of the problems I've had....... YET!! But thanks for mentioning it; might be something worth checking periodically. I've not heard of any recall and all the FL issued ones have been performed on my coach.

And to check it, I suspect the hatch door in my bathroom floor will have to come up. Anyone with a 390RB ever tried to open that hatch?

Boowho??
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Old 04-11-2013, 06:49 PM   #3
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] Three of four bolts holding hub to engine had broken and the fourth had backed out about 2mm. Repair required removal of radiator and removal of broken bolts. Fifth hole drilled and tapped to improve strength of hub to engine interface by ATC Freightliner techs in OKC. They also commented they'd seen several of these types of repairs because original bolts are of inadequate strength and penetrate engine block only about 12mm.
I would think that if Freightliner knows that the bolts are inadequate and don't go into the block far enough, that they would recall those chassis that are effected and replace the bolts. It seems like it something that should warrant a recall.
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Old 04-11-2013, 09:30 PM   #4
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Originally Posted by Hawkeye Driver View Post
I bought a 2009 390BH Berkshire in May 2011 with 12500 miles. Recently at about 31600 miles, I experienced a sudden engine overheat. Long story short, radiator hub had detached from back face of engine and fan tilted and seized in shroud. Three of four bolts holding hub to engine had broken and the fourth had backed out about 2mm. Repair required removal of radiator and removal of broken bolts. Fifth hole drilled and tapped to improve strength of hub to engine interface by ATC Freightliner techs in OKC. They also commented they'd seen several of these types of repairs because original bolts are of inadequate strength and penetrate engine block only about 12mm. Radiator hub is a Freightliner add-on to the Cummins 360 engine before coach ready chassis delivery to Forest River. Has anyone else seen this problem? Is there a DOT recall or tech advisory from Freightliner, Cummins or Forest River? I was fortunate that the fan didn't disintegrate and damage the radiator, but my fan still had to be replaced because of sudden-stoppage fractures. Cost of repair almost $2400. Any enlightenment welcomed.
Sounds like bolts failed due to strength issues. Since they were required to be drilled out, they probably weren't loose and they didn't pull out. Rule of thumb is bolt depth should equal or just exceed the diameter, in this application, probably set with lok-tite. You didn't mention the bolt diameters but more than likely 12mm is maybe just about correct.
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Old 04-11-2013, 11:18 PM   #5
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Radiator Fan Trouble Reply

Thanks to each of you for your response. I just checked some spec bolts I have on hand; they're about 6mm dia, so the 12mm depth is probably in accordance with engineering practice. FL in OKC said each time they get one of these, they replace with stronger spec bolts than the originals. No history on failures of their repair. They say that bolts backing out is as much a problem as strength failure. Their fifth bolt custom add-on sounds like a real good idea. If hub comes off completely, fan shatters and takes out radiator, wiring and fluid lines. I fully agree that FL should seriously consider an investigation of this problem and a possible recall, but have no idea if they read any of these comments. The problem has apparently been around for several years. (Anyone know how to get DOT interested investigating for a recall?) As for access, it's a nightmare on my 390BH. Ironically, I had a radiator clutch failure last July that required FL in OKC to pull floor boards for access (I'm getting to know their techs personally:-). They had to cut thru carpet, OSB and pull multiple fasteners, but now I can get to the area much easier. Expensive clutch, but cost of gaining access even pricier. Guess it's best to pass this experience on as a heads-up to operators of Cummins/FL configuration on RVs.
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Old 04-12-2013, 02:32 PM   #6
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Thanks to each of you for your response. I just checked some spec bolts I have on hand; they're about 6mm dia, so the 12mm depth is probably in accordance with engineering practice. FL in OKC said each time they get one of these, they replace with stronger spec bolts than the originals. No history on failures of their repair. They say that bolts backing out is as much a problem as strength failure. Their fifth bolt custom add-on sounds like a real good idea. If hub comes off completely, fan shatters and takes out radiator, wiring and fluid lines. I fully agree that FL should seriously consider an investigation of this problem and a possible recall, but have no idea if they read any of these comments. The problem has apparently been around for several years. (Anyone know how to get DOT interested investigating for a recall?) As for access, it's a nightmare on my 390BH. Ironically, I had a radiator clutch failure last July that required FL in OKC to pull floor boards for access (I'm getting to know their techs personally:-). They had to cut thru carpet, OSB and pull multiple fasteners, but now I can get to the area much easier. Expensive clutch, but cost of gaining access even pricier. Guess it's best to pass this experience on as a heads-up to operators of Cummins/FL configuration on RVs.

So, you are saying that the fan is indeed clutched? With a rear mounted radiator as on my 390RB, I figured the fan had to run all the time. Even when I first start the coach (before it warms up) the fan is running on mine.

I'm told that the fan takes up around 70 HP to turn. That's an incredible claim, but was told that in a truck driver's class.

Boowho??
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Old 04-12-2013, 09:48 PM   #7
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Yes, the fan is clutched, but I think it runs pretty much all the time. The trouble I had last summer (before this hub/bolt problem) was intermittent operation of the fan. I was on a long trip to east coast. Overheats seemed to occur on initial start, then it managed to reset itself after a few miles and worked ok rest of each day. Finally got to the point where it wouldn't operate at all after I returned home. Couldn't risk driving 70 miles in July heat to FL in OKC, so had to have it towed. Clutch is electrically controlled by temp sensors on engine. The part costs about $661! I had not heard the 70HP claim before, but it sounds reasonable. It's about 30" dia with about 10 blades at steep pitch. When it's working well and during heavy load (hill climb in heat), I could actually hear and feel the fan assume higher than normal rpm. If you ever have trouble like this, know that the overheat warning occurs about 223degF.
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Old 04-15-2013, 04:21 PM   #8
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Hawkeye,
You indicated that the engine is a 360 (I am assuming that it is a 6.7l ISB) that this happened on. Do you know when the chassis or engine was manufactured?
Thanks.
Tom
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Old 04-15-2013, 05:10 PM   #9
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Tom,
Let me do some digging and I'll tell you as much spec and date info as I can. I'll get back to you soon.
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Old 04-16-2013, 05:02 PM   #10
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Tom,
My mistake on the horsepower. Original cert of origin for chassis says 350HP and is dated March 26, 2008. Owner's Manual for engine says ISB CM2150. Do you have the same installation?
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