Onan quite diesel 7500 shuts down 45 min

[bhfranklin]

My onan quite diesel with cummins engine shuts down after about 45 minutes of running. It has been serviced in the last couple of months, is full of oil and coolant. The light flashes 3 times which indicates according to the sticker needs service.... The generator has right at 500 hours and starts and runs great,,, for about 45 minutes. Its mounted in a 2000 Edeavor. Doesn't seem to make a difference about how much load. I also noticed both rear jacks leaking fluid this trip so I'm looking for my wallet.... Thanks in advance for any ideas.

Bill

[carmantx]

I did some research on this because ours will shut down also. Two things I would do.
1. get all air out of the cooling system. Squeeze the exposed coolant hoses many times with the cap off. (gen not running). After that, run the generator for a while with the cap off
2. these have known issues with the thermostat sending unit. If 1 doesn't work, then try to replace the sending unit.



Good luck. number 1 worked for us, but I will probably order the thermo unit just in case.

[Gary RVRoamer]

The "3" is just the first part of the trouble code - you need to get the second digit to find out what is wrong. See page 22 of the Onan Service manual for info on reading the secondary code and what they mean. Download here if you don't have it:

http://www.cumminsonan.com/www/pdf/m.../981-0161C.pdf

Some likely causes are overheating or low oil.

[bhfranklin]

Thanks for the input. I did not understand how to get the secondary code. I have down loaded the manual and will get out to the rig and get the rest of the code. That should get me pointed in a direction. I'll report what I find. Thanks again.

[BlueLine]

Bill,
For a 1 or 3 blink code momentarily press stop to bring up the secondary level. This code consists of 1,2 or 3 blinks. a bried pause, and then 1 to 9 blinks, the combo of the two will be your fault code. Example :blink blink pause blink blink blink = Fault code 23

[bhfranklin]

I went out to the rig and checked the code properly. It is code 26, below speed target. The manual says to reduce the load or prime the fuel system. When it shut down only 1 heatpump was running and it was cycling on and off because it wasn't that cool out so I don't suspect load is the issue. I change the fuel filter along with other service about three months ago and didn't have this issue before that. I did bleed the system as described in the manual but it is my intention to bleed it again and run the unit again. With other diesels I have been familiar with in the past if it started and ran it was bled. I guess the newer electronic stuff its different. If this indeed is the issue how do I clear the fault code? I am at the end of vacation so I won't get to work on it til next weekend but I will report what I find. Thanks again for any input.

Bill

[B Bob]

I had a similar problem with my Onan 12,500. It seems the fan belt is hard to get to, at least on our generator it is. So when I had mine serviced a year ago the lazy techs did not bother to check the condition of the fan belt. Finally after complaining many times and replacing two thermostats coolant and so on they looked at the fan belt. Guess what, it was trash. So they replaced that and that was the last time mine shut down. Might be your problem.

[bhfranklin]

The fault code indacates an issue with the engine not reaching target engine speed as the problem but I intend to check the belt and everything I can get to thourly when I get out there this weekend. My generator does not pull out the front like some do so my only easy access is to go in the service area in the bottom. I'll let you know what I find.

Thanks, Bill

[Downsizer]

Also, be sure oil completely FULL... same problem with mine..... only 1/2 qt low, thought all ok,,,,, talked to Onan... needs to be full since it has a shut off system if it gets too low.... 1/2 qt is too low...... fyi....