Thomas Schwaiger
Murrieta, CA 92562
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Joined: 10/26/2001
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Hello All,
Sorry for the long post but I thought the more detail the better chances in finding the problem.
I'm sure everyone is sick of generator problems by now but here it goes:
I have a 7.5 quiet diesel Onan and for the last 6 months has been shutting down after 15-20 minutes.
I read the codes and it shows "33" ( --- --- --- --- etc.)which according to the trouble shooting means overheating.
I took the front cover off after discovering that the cooling hose from the radiator to the pressure cap is about 10" too long, (probably due to the fact that they thought one would want to pull it out from the compartment via the little lid).
The problem with the excess hose is that when you push it back in it KINKS! So there is no way that the radiator is ever able to pull coolant from the overflow reservoir (or send it there for that matter).
So, the first thing I did was check the fluid temp and it showed 120 deg. F before it shut down.
So I shortened the hose, flushed the whole system, changed the oil and fuel filters and tried again. Still shuts down after 15 min. 
So I explain the whole situation -with symptoms and all- to my service guys and suggest to them that it HAS to be the temp sensor or similar.
They redo the whole procedure, change the temp. sensor and turn it on; still shuts off. $ 350.-
Onan says the generator needs to come out for further testing and I'm out of patients. Could it be in the fuel system, maybe the injectors? (But that would probably show on the codes).
On the first-level Fault code it says: "Engine coolant or inverter heat sink temperature exceeded design limit".
Could it be the inverter doing it, that thing DOES get hot in the basement.
PLEASE help,
Thomas
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deandec
El Dorado Hills, CA
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Joined: 09/26/2001
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Disconnect the coolant sensor and see if the generator continues to run?
Is fan belt running ok?
120 degrees is certainly not too hot.
Dean
95 CC Magna, Jeep GC
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Gale Hawkins
Murray, KY
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Joined: 07/22/2007
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Yes seems to be the answer. The problem with computers are the sensors that gather the info that throws the codes.
The first step could be to isolate/defeat input coming from the inverter. If it still shuts down then from the temp sensors. 120 is not over heating I would guess.
It could be the or one of the computer boards are defective or some connector is not well connected. The good part is it seems like the generator makes power OK but the computer is shutting it down for some reason.
After recently learning more about the computer system on our older Kohler than I ever intended to know I have a new respect for how simple and yet complex they are and how well they work until something messes up with the communication features. I do not know your gen set but I do know electronic trouble shooting to some degree thanks to the USN and some experience over the years running a technology company.
Have you googled this problem? Trace out the logic on your schematics that should be in your manual or get them from Onan. Look at the paths of those two inputs and something may jump out at you.
Pulling it out may be the cheaper option since you have spent $350 with no results. If it was not you then someone else posted about the same issue recently.
See post 8863. Text is below for one idea.
had the same problem, turned out to be the thrmostat. what was hapening
was the thermostat was defective and was telling the brain that the gen. it was overheating and would shut down every time after running for 2 minutes good luck
* This post was
edited 07/29/09 10:23pm by Gale Hawkins *
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Thomas Schwaiger
Murrieta, CA 92562
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Thanks for your quick answers.
They apparently changed out the sensor AND thermostat and it's still doing it.
I'll pick up the MH from them today and have a look myself.
Maybe it will give me a different code after the (failed) repair.
I'll run it without load and the inverter turned off, maybe that will tell me something.
Thomas
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travisc
Pacific NW
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Joined: 12/14/2008
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Not sure this will help- but you might want to take it directly to Cummins if you have one in your area. I wanted to get an airfilter and spark plug from my gas 4.0KW Microquiet. The RV Parts department said we don't carry that stuff and can't get it. This is the 3rd time this shop has been less than helpful.
Of course 4 miles down the road there is a Cummins shop- and as I drove by yesterday I see a sign that says RV's and Trucks enter here... (this was Renton, WA)
Good Luck
Winnebago Access 24V
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kg5388
memphis
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give us the full model number of the genset as there are several 7.5 quiet diesels
the serial number or at least the first letter and 2 numbers will help as that will give us the age of the henset
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Generator Jim
Conway, SC
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Tom
The inverter you mentioned in your first post is not the one in the MH basement. It is the one built into the generator set.
JimL
Jim & Jane Latour
08 Chevy 3500HD, crew cab, dually, Duramax/Allison
05 Wilderness Advantage AX6 365 BSQS, Onan 3.6KY
Retired AF CMS (E9) Power Generation and Onan RV genset Level III tech
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Thomas Schwaiger
Murrieta, CA 92562
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Uhmmm, quoi?????
What inverter are they talking about then? Does the generator have a separate inverter to "invert" to 110V?
I didn't pickup the rig afterall, so I don't have the model# yet. As soon as I do I post it.
Thomas
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kg5388
memphis
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there are some quiet diesels that are inverter style gensets and some that are not that is why it is so important to know the model number
it also helps to know the year it was made to look up service bulletins for example the early inverter quiet diesels did not get along with the rv xantrex 2000 inverters
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Thomas Schwaiger
Murrieta, CA 92562
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Hello All,
I finally got the rig back and still without generator.
The model# is 7.5 HDKAJ11451H Spec: H serial# F 030512257.
They replaced the temp sensor and thermostat, to no avail.
Help please?
Thomas
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