Radiator Fan Trouble

[Hawkeye Driver]

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.

[boowho]

Originally Posted by Hawkeye Driver

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??

[tmmar]

Originally Posted by Hawkeye Driver

] 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.

[VinceU]

Originally Posted by Hawkeye Driver

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.

[Hawkeye Driver]

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.

[boowho]

Originally Posted by Hawkeye Driver

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??

[Hawkeye Driver]

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.

[tmmar]

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

[Hawkeye Driver]

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.

[Hawkeye Driver]

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?

[tmmar]

Hawk,
I have a 2008 coach with a 340hp engine. The manufacture date of the engine is December 5, 2007. I have the same CM2150 engine. Did Freightliner say if the problem affected certain engine manufacture dates?
Tom

[Hawkeye Driver]

The only thing I learned from the tech who worked on my engine in OKC was that they've seen "several" of these hub failures over the years. Mine, however, was the first they'd seen in two years so it's not too frequent. I'd really like to talk to FL at the corporate and engineering level, but doubt if they'd be very forthcoming. I used to live next to a DOT rep in the DC area who worked recall issues. He said the first reaction of most manufacturers was to deny, stonewall and dig their heels in. Recall usually had to be forced on them from high levels. Might be worth your effort to have a FL RV service facility look at your fan hub and check the bolts. Access is difficult, but it may be worth it. Not sure what to do about mine in the future, but it will be checked by myself at least. Wish I could be more specific. Let me know if you ever find out anything.

[hark582]

I had the same problem with my 2008 Berkshire. The repair shop said that there were only 4 bolts to secure the fan hub. In their opinion that was not enough to handle the stress placed on it. The repair shop suggested that I contact Freightliner to see if there was a recall. I did that and the Rep at FL said there was no recall but they now offer for purchase a new fan hub with FIVE bolts. This tells me that they know of the problem but they are not going to do anything about it. I then sent a letter off to Good Sam's Club Hot Line to see if they could offer some assistance as I also had to pay over $2000 for the repair work. Good Sam sent a letter off to FL. They did not even get a response from FL so they sent off a second letter to them after a few months. Again no response so Good Sam declared the matter to be complete. Needless to say I was not very happy with this. Someone needs to put pressure on FL to make good on this matter.

[tmmar]

Maybe we should start a poll to see how many have been affected by this. I guess we should log the year of the coach, when the engine was manufactured, and the mileage the when the failure occurred. If anyone can set this up it would be a big help in possibly getting Freightliner to do something about this problem.

[boowho]

Originally Posted by tmmar

Maybe we should start a poll to see how many have been affected by this. I guess we should log the year of the coach, when the engine was manufactured, and the mileage the when the failure occurred. If anyone can set this up it would be a big help in possibly getting Freightliner to do something about this problem.

Good idea on the poll........

I'd also like to know if they made mods to the newer engines to correct the problem. Who actually makes the fan assembly; Freightliner or Cummins??

Boowho??

[Hawkeye Driver]

boowho: My understanding, talking to FL repair shop in OKC, is that the fan hub, fan, shroud and other accessories are added by FL to the engine after they receive it from Cummins for installation on their chassis before they sell it to Forest River. It's probable this configuration also shows on chassis assemblies sold to RV manufacturers besides FR.

tmmar: A poll would be a good idea, but it would only be anecdotal and dependent on owners being a member of a forum like this and interested in sharing a story. Not sure how else we'd be able to find others with this problem.

hark582: Sounds like you did what I was about to. Learning that there's a five bolt hub available is evidence it's happened often enough they made engineering mods at the manufacturing level. My tech in OKC drilled and tapped a new hole for mine. Good Sam's efforts were not helpful at all. Two no-responses is a row doesn't solve a problem. It just allows them to not expend anymore effort.

I'm thinking in terms of doing a google search to find the recall desk at DOT in DC and interest them in this problem. DOT might have the horsepower to ask FL to ask about the problem. hark582's news that FL now sells a 5 bolt hub is evidence there's a recognized problem at FL. I'll be back if I find anything.

[VinceU]

Originally Posted by Hawkeye Driver

boowho: My understanding, talking to FL repair shop in OKC, is that the fan hub, fan, shroud and other accessories are added by FL to the engine after they receive it from Cummins for installation on their chassis before they sell it to Forest River. It's probable this configuration also shows on chassis assemblies sold to RV manufacturers besides FR.

tmmar: A poll would be a good idea, but it would only be anecdotal and dependent on owners being a member of a forum like this and interested in sharing a story. Not sure how else we'd be able to find others with this problem.

hark582: Sounds like you did what I was about to. Learning that there's a five bolt hub available is evidence it's happened often enough they made engineering mods at the manufacturing level. My tech in OKC drilled and tapped a new hole for mine. Good Sam's efforts were not helpful at all. Two no-responses is a row doesn't solve a problem. It just allows them to not expend anymore effort.

I'm thinking in terms of doing a google search to find the recall desk at DOT in DC and interest them in this problem. DOT might have the horsepower to ask FL to ask about the problem. hark582's news that FL now sells a 5 bolt hub is evidence there's a recognized problem at FL. I'll be back if I find anything.

Here's an immediate step you folks can take, doesn't change inherent design.
The existing bolts were reported at 3mm diameter x 4, that's pretty anemic for the load. If the bolts are Class 8.8 Metric which I suspect they are, that isn't much to rotate that high horsepower load. You can change the bolts to a much higher grade strength both shear and tensile in Class 12.9. Set the bolts in Loktite and wait for the factory mod. BTW the strength value of this upgrade is more than twice the 8.8 class standard bolts. How bout NTSA in addition to Dot?
NTSA provides forms on line to complain of unsafe conditions.

[tmmar]

Originally Posted by Hawkeye Driver

I'm thinking in terms of doing a google search to find the recall desk at DOT in DC and interest them in this problem. DOT might have the horsepower to ask FL to ask about the problem. hark582's news that FL now sells a 5 bolt hub is evidence there's a recognized problem at FL. I'll be back if I find anything.

Hawk, if you find anything out as who we can notify about this, let us know so we can all send an email. Maybe if they get a number of complaints, something will be done to help us.

vince, where can these class 12.9 bolts be found?

[OldCoot]

Originally Posted by VinceU

Here's an immediate step you folks can take, doesn't change inherent design.
The existing bolts were reported at 3mm diameter x 4, that's pretty anemic for the load. If the bolts are Class 8.8 Metric which I suspect they are, that isn't much to rotate that high horsepower load. You can change the bolts to a much higher grade strength both shear and tensile in Class 12.9. Set the bolts in Loktite and wait for the factory mod. BTW the strength value of this upgrade is more than twice the 8.8 class standard bolts. How bout NTSA in addition to Dot?
NTSA provides forms on line to complain of unsafe conditions.

Something is wrong here, a 3 mm bolt is only 0.118". That has to be an error.
Maybe 8mm which is .315". I would tap them out to a 3/8" UNC and use gr. 8 bolts.

[VinceU]

Originally Posted by tmmar

Hawk, if you find anything out as who we can notify about this, let us know so we can all send an email. Maybe if they get a number of complaints, something will be done to help us.

vince, where can these class 12.9 bolts be found?

Tom,
I used Yahoo for "Metric bolt standards" and "Metric bolt sizes". Tons of pics and tables with vendors showed up.