Could Low Oil in my Generator Cause This?

Hi,

I think low oil, or possibly "thin oil", might be your problem. I have an Onan 7000 gas generator on our motorhome. On several different occasions, usually while travelling down the road, I've had the electricity knock-off with the generator shutting down due to low oil. However, I have also observed, on occasion, the electricity gets interrupted yet the generator keeps running. About 30 seconds later, the transfer switch reconnects and all is fine.

Here is what I have learned.

Always check the generator oil and if it's below the full line, I top it off before heading out on the road. We generally run our generator while rolling down the road, so each day of travel, I'll check the oil.

I always use the thickest oil possible as specified by the owner's manual for the temperature range of operation. And it might be psychological, but I seem to have had better luck (more consistent generator operation) with a single viscosity oil, rather than the multi-viscosity oils. The thinner oils slosh around more and that will trick the sensor into thinking that there is a low oil condition and sometime initiate a shut-down. Sometimes, as I mentioned, the engine sputters enough to disconnect the power, but the engine will keep running.

It's taken me a number of years to develop this routine, but I haven't had a generator shut-down due to the oil in several years.

Good Luck,

~Rick

Very doubtful that low oil caused it. I would suspect that the brushes lost contact or a wiring connection vibrated loose. Check all your wires and connectors to make sure they are tight. Check the transfer switch connections. And take some time to clean the brushes on the genny.

Low oil will shut the generator down. In your case you loss power but the generator remained running so NO it's not a low oil problem.

NO, Low oil will only kill the running of the Genset. Will NOT affect the 120 output. Doug

Low oil will trip the motor side of the generator. The electrical generation side can in effect disconnect if there is a problem with output voltage or frequency. The problem you're going to have is the problem appears intermittent and unless the generator's built in testing will store fault codes determining what the problems is will be difficult.

I doubt it would shut off the load, rather than just shut off the engine entirely. An engine running without sufficient oil unloaded is not going to fair much better than one running loaded...probably a little better, but still likely to be damaged before too long if the oil is sufficiently low.

Methinks you may have a problem with your transfer switch or possibly a loose connection between the generator and the transfer switch. If that's the case, it's something you ought to get fixed pretty soon, as these are the sorts of problems that can cause things to get hot enough to smoke or burn.

These generators are quite finicky when it comes to oil....Mine shuts down when it gets just a bit low....that's for safety so you don't blow the engine up.


I am retired AF also 1979-1992 B52 Crewchief 1979-1982 then F -15 Crew chief/phase dock Chief Eglin AFB 1982-1989/ 1989-1992 Kadena AB Okinawa Hardbroke Chief.