Discovered what seems to be motor oil in the air cleaner outlet tube just forward of the throttle body---enough that it had pooled in the folds of the rubber bellows just forward of the TB. Specifics: '00 E250 5.4l gasoline w/241K miles.

I typically lose about one quart every 3K miles between oil changes but no signs of fouled plugs or inordinately bad performance considering the mileage. Any ideas how this oil is deposited in this tube?



Thanks

 

It is from the crankcase vent system, replacing the PCV with a Motorcraft one could help. You can also use oil separators on both the tubes to catch the oil.

 

I did change the PCV valve recently---Motorcraft all the way! This was before discovering the pooled oil as I'd never before had reason to look inside the intake ducts.

The only "problem" I had was the new PCV valve had a different outlet port orientation; 90 degrees as opposed to straight up facing. Certainly a small problem but the dealer told me it was the called for part and can't be that big a deal.

Tubes were cleaned out and in a few thousand miles I'll check again just to be sure all is well.

Thanks for the help Galaxie!