So I just did the breakin oil change on my cummins gas generator. I used 10-40 and the oil level is right where it should be. When I fire it up after about 5 min it shuts off and gives me fault code 2. Low oil pressure . Has anyone else had this happen ?

I had it happen when trying to use 10-40 oil. Changed to 30 wt. and it is no longer an issue. Evidently cavitation was causing a low pressure reading.

Owners manual calls for 15-40 or 30Also, here's a quote from the manual,Oil FiltersGreen Label Parts oil filters feature valves that allow oil to bypass the oil filterduring cold starts, or if the filter becomes plugged. Other manufacturers’ oil filtersoften do not have bypass valves. As these “will-fit” filters trap debris, oil pressurestarvation can occur, leading to high oil pressures, failed gaskets and even enginedamage. Other “will-fit” oil filters may contain a bypass valve, but it’s not possibleto determine at what PSI the valve opens. If the setting is too high, the filter’s paperelement can be damaged during a cold start rendering it useless, or cause oilstarvation to the engine.

Thanks. Yea, caught that I used the wrong oil. Going to change it again today and see if that does the trick.

bman. Make sure you use an ONAN oil filter. Or Generac, if you have a Generac. Onan is real strict on the filters. Go back and read Dakota's post. He is right on the money. We get this many times every month at the shop. Wrong oil/wrong filter.

5500 generator keeps shutting down after break in oil change

_plit
Explorer
Mar 11, 2015
oops nevermind, sounds like you are dealing with a new one! arggh
_plit
Explorer
Mar 11, 2015
there was a point (dont recall exactly when) that cummins/onan replaced or removed a inline fuel filter and when you did a service on them they would do what you are describing. I can't remember what part was replaced, when or if you simply removed the old one or replaced it with a different part number...I keep thinking it had to do with starving the carb of fuel for some reason...Sorry its been a few years since i had to deal with that...I didnt find out about until one of my friends went into the Onan dealer and spoke to them...
nayther
Explorer
Mar 11, 2015
Strabo wrote:
nayther wrote:
strange, have used 10/40 in mine since first oil change, never an issue. Onan Marquis gold 5500

Same here...

I would be more prone to suspect the filter if the OEM was not used based on the above comment regarding builtin check valve. I used an aftermarket one once, it ended up being more expensive than the OEM, but it did crossover directly (RV store was closed so had to go to the auto parts store). Since then just used the OEM filter and 10-40 no issues.
Strabo
Explorer
Mar 10, 2015
nayther wrote:
strange, have used 10/40 in mine since first oil change, never an issue. Onan Marquis gold 5500

Same here...
nayther
Explorer
Mar 10, 2015
strange, have used 10/40 in mine since first oil change, never an issue. Onan Marquis gold 5500
RUFFSTUFF
Explorer
Mar 10, 2015
Thanks for the info!
Macman83
Explorer
Mar 08, 2015
This is good information to know. I would not have thought that the oil viscosity would make that much of a difference.
bman916
Explorer
Mar 07, 2015
Just did a new new oil change wirh the right oil..... Yep, works fine now....
bman916
Explorer
Mar 07, 2015
I did use the Onan filter
chevyman2
Explorer
Mar 07, 2015
bman. Make sure you use an ONAN oil filter. Or Generac, if you have a Generac. Onan is real strict on the filters. Go back and read Dakota's post. He is right on the money. We get this many times every month at the shop. Wrong oil/wrong filter.