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 > 7500KW Onan Quiet Diesel, code "33" over heat! ??

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Gator48

Branford, Florida

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Posted: 07/25/12 11:16am Link  |  Print  |  Notify Moderator

I have 6 of these generators in current use. 5 commercial and our coach. 99% sure you will probably find the fan belt is loose or damaged.


Good Luck

FIRE UP

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Posted: 07/29/12 11:46pm Link  |  Print  |  Notify Moderator

Gents,
To all who've answered, I apologize for not responding more quickly. We've been traveling and much of the time we've been at RV parks with hookups and have not had the need to use the genny. But, the one or two times we used it at a non-hook up spot, "Silver Lake National Forest Campground", it worked flawless and the wife was using it for her 1800 watt hair dryer. Yep, the rest of the campground goes dim when she uses that thing.

Anyway, there IS a code 33 in the Cummins/Onan owners and trouble shooting manual. Under that code, it lists several reasons for possible "over heating". I won't list them here, just suffice to say there is a list. I've checked about all the points they list and all are good.

Yes, the fan is spinning freely, putting out a ton of air, out the outlet that is. And Smitty, a buddy and I pulled the top panel off that genny and checked as much as we could, by eye and all is well and good with with the belt, water pump and more. The belt is in great shape and is tight.

The oil level was checked right before we left home, as well as the coolant level.

zmotorsports,
I'm not sure what the elevation of Bishop is, I think it's around 4k or 5K feet. As Smitty says, his too developed the same problem, IN BISHOP!!!! As stated, this genny has ran and ran and ran, and, all the while powering up the A/C basement air just fine, until this incident. As for the hours, we had 65 on it when we purchased the rig just over a year ago. We now have 108 on it.

The cover for the air cleaner was removed and the air cleaner inspected. It's perfect. No debris, no clogging. I cannot vouch for the fuel filter on the genny, I have no idea where it is. I'll have to do some searching around for it.

Popsie,
Just for logistics, our ID plate looks like this and has the "7.5HDKAJ" MODEL, which, is not even in the list on the Cummins/Onan site unless you go to the RV section.



Gator,
Well Sir, as stated earlier, I pulled the top panel and physically checked the belt and it's in great shape and is tight as it needs to be. Not guitar string tight but, tight enough.

As for the second level fault code, I've erased the code a couple of times and it came right back as code 33. It would not blink any other sequence no matter how I pushed the button/toggle. And, if I pushed it at all, it simply erased the code and would not blink at all.

Now, here's some more for you boys possibly think about in this ordeal. When we first purchased this coach, just over a year ago, the genny would start, as normal. That is, if it was dead cold, and below a certain temperature, you would push the start button and it would NOT turn over until the timer/glow plug heater told it to. Then it would crank for about 1 second and start. But, in the last few months, even if the genny is real cold, I push the start button and it immediately cranks, and cranks and cranks and cranks until it starts to spit, bang, far.. cough, choke and finally it starts up. All the while it's putting out some serious white smoke. That, I assume is unburnt diesel.

Now, does all this have anything to do with the over heating incident, I have no idea? Is the sensor/timer for the glow plugs related to the sensor for overheating? Again, I have no idea. And, here's one more thing. I have another problem with it. In an inspection a few months ago, and again on this trip, I found pieces of magnetic material, stuck to certain metallic parts of the gen inside the operation area.

Upon closer inspection, we found out what those pieces were. I'm not sure what you call it but, it appears to be part of the fan/rotor. As the fan spins, it's also spinning what I would call the rotor, maybe "stator". I'm not really sure of all the part names here. But, the "armature" is the part that has a zillion feet of copper wires on it and it stays put, right? The rotor, or stator I guess, is the part that rotates, correct?
Well, that rotor/stator has a number of parts that come very close to the armature. But, based on the spacing of all that's there, there's one missing. And, it appears it has broken up and is not there. The genny is putting out what appears to be good 110AC but, I don't have any sophisticated equipment to check if it's out of phase or any other problems.

Now, here's the problem. I've been all over the Cummins/Onan parts and accessories pages and they apparently don't want you "me" or any other layman getting there hands on the interior parts. Yes, they have things like mufflers, piping, a couple of switches etc but, I've failed to find either of the possible sensors I may need and, that fan/rotor/stator that I KNOW I need. If anyone has that detailed parts list, that that model genn in the picture above, I'd surely appreciate it. Sorry for the long novel here but, just trying to get everyone the big picture.
Scott


Scott and Karla
SDFD RETIRED
2004 Itasca Horizon, 36GD Slate Blue 330 CAT
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zmotorsports

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Posted: 07/30/12 06:05am Link  |  Print  |  Notify Moderator

Scott, I the parts of the generator you are referring to are as follows for clarification: the part that spins internally between the windings is called the rotor, the windings themselves is called the stator (stator assembly).

As far as the fuel filter, if you open the side door where you can get to the oil fill as well as the coolant surge tank, look straight down that side panel towards the rear. The fuel filter is located on that same side at the bottom of the generator enclosure. It is easiest to access by removing the panel and accessing from underneathe. The fuel lines are attached to thru bungs in the bottom of the generator enclosure.

I am not certain on the glow plug timer but I don't think it has anything to do with an overheating condition.

Mike.


2003 Monaco Dynasty/ 26' Haulmark Edge trailer
2011 Jeep Unlimited Rubicon


cbeierl

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Posted: 07/30/12 08:18am Link  |  Print  |  Notify Moderator

The fuel filter is accessed from the bottom hatch that also allows access to the oil filter. It's a boxy silver element right in front of (above) you when you open the little door.


Chris Beierl
2005 Winnebago Vectra 36RD


horizon36

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Posted: 07/30/12 08:29am Link  |  Print  |  Notify Moderator

Mine did the same thing and I got a 33 code (yes, it does exist). The manual says it could be the belt, old coolant etc. Mine did the same on restart, shut down after a very short period of time. Let it cool down for 20 minutes and it finally kept running. Went to a trusted shop in Vegas and they changed the coolant for me. While doing that we found we couldn't get the proper amount of coolant back into the unit. We would start it up and it would shut down and then burp. Learned that the thermostat was sticking shut and that that was the main problem. It seems that the new coolant has helped eliminate the problem so for now I don't have to drop the generator out of the coach to service it.


Live Long and Prosper.

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FT since August 2010

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dkreuzen

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Posted: 07/30/12 04:15pm Link  |  Print  |  Notify Moderator

catallison777 wrote:

My 7.5 did the exact same thing. It turned out to be the temp sensor. This is pretty common on the 7.5 quiet diesel. Its only about a $17 part.


X2

The sensor had come apart inside the block and if the ECU doesn't see the engine heating up to temperature it shuts it down. The gen was removed and the sensor, thermostat, coolant, and belt replaced for $472.


Dennis
2012 Monaco Knight 36PFT
2014 Jeep Grand Cherokee Overland
2005 Jeep Wrangler Unlimited Rubicon
2007 16' Car Hauler Trailer


FIRE UP

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Posted: 07/30/12 08:33pm Link  |  Print  |  Notify Moderator

zmotorsports and Chris,
Thanks a heap for directing me to the fuel filter and more on my gen. And, thanks also for teaching me the correct terminology on those particular parts. Now, if I could just get my hands, or eyes, on a parts sheet or PDF layout, I'd know what to order and or ask for. As stated earlier, we've only had the coach for just over a year and we've got service records for the generator just prior to our taking ownership of the rig.

But, being serviced and having problems crop up after the fact, is two different things. We're in Grants Pass Oregon at present and, we're in RV Parks with hook ups so, the genny is not being tortured for its service very much right now. As for installing the rotor, I usually do my own work so, if and when I can order it, I'll see if I have what it takes to do the install. I can barely see the rotor but, if I look though some openings, I can verify that I have a broken section of it. As far as seeing just what it would take to get it out and back in, that remains to be seen and, whether or not the genny has to be removed from its sliding tray.

Thanks again to all who've responded here. It's very much appreciated.
Scott


cbeierl

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Posted: 07/30/12 09:12pm Link  |  Print  |  Notify Moderator

At some point in the early 2000s I believe Onan had a problem with magnets coming unglued from the rotors, requiring expensive replacement. I don't have any further into on that, but you might want to search on that and see what comes up.

FIRE UP

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Posted: 07/31/12 12:00am Link  |  Print  |  Notify Moderator

Thanks Chris, I'll do just that.
Scott

fcooper

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Posted: 07/31/12 06:25am Link  |  Print  |  Notify Moderator

cbeierl wrote:

At some point in the early 2000s I believe Onan had a problem with magnets coming unglued from the rotors, requiring expensive replacement. I don't have any further into on that, but you might want to search on that and see what comes up.


Yes, that is correct. I was one of the unlucky ones. Onan knew they had a problem and, from what I've been told, they extended the warranty for original owners only. If you purchased a used coach, the repair is on your budget. My cost at a Cummins/Onan repair facility was about $4,000. The exploding rotor took out the stator. Holiday Rambler never intended for that genset to be removed as they had to cut some aluminum support for the front cap door to be able to remove the generator.

At $4,000, you can do a lot of "do it yourself" repairs. Good luck with yours. Maybe you got lucky and only lost a small piece.

Fred


Fred & Vicki
Richmond Hill, Ga
2000 Holiday Rambler Endeavor/Freightliner/330 Cat
2000 Honda Odyssey toad w SMI Silent Partner braking system
TST507 TPMS

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