Microlite 4000 Dumping Oil

[Rick N Donna RVN]

We have about 500 hours on our second Microlite 4000 (over 7700 hours on the first unit) and it has suddenly started dumping oil on the ground.

I thought it might be a plugged crankcase vent problem and disconnected the hose/tube that runs from the top of the valve cover to the air cleaner housing, but have not tried to run it again with this hose disconnected.

After ~10 minutes of running, there's a 1.5 square foot oil puddle on the ground. The oil is dripping from the oil plug cover plate on the bottom of the gen. I change the oil (versus a shop) and the drain plug is tight and does not appear to be the source of the leak.

This unit originally (@ less than 50 hours) had a TSB on the reed valve that controls the crankcase ventilation (I think this is correct) where the Onan factory tech applied the TSB fix. This problem caused a lot of oil vapor in the air filter housing and on the left side of the gen. cabinet (inside the cabinet). This symptoms still exists and may be part of the problem.

The leak was not a slow leak that steadily got worse and seemed to begin all of a sudden. I cannot see a source of the leak when using a flashlight and looking inside the gen cabinet. We're on the road, so it's not the best time to be troubleshooting.

Any assistance or suggestions would be greatly appreciated!

Rick