When you open the air filter housing, you will see that the oil separator has a couple of metal "tabs" that hold the top on. That seam can leak a considerable amount of oil into the air filter housing. Clean real well with brake cleaner, to get good adhesion, and seal with RTV. Once I did this, the oil in the air filter assembly was negligible. Be sure and let the RTV cure as you absolutely don't want any of it to come loose and end up down in the oil pump area.

Oil by the power steering pump? Hmmm, how are your oil cooler lines? When one of mine leaked, it left a lot of oil on the drivers side of the engine bay. If they are leaking badly, they need to be replaced ASAP as a rupture can ruin an engine in short order.

I don't know your location,(you might include it in your signature, it helps) but lightweight synthetic will definitely magnify any oil leaks as you probably know already. How lightweight are we talking about?

Ultimately, 1.5 qts. low on an 8 qt. system is not enough to warrant major engine issues if you are using very lightweight oil and have leaks.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )