oil everywhere

i am about to replace the head gasket on '84 190E. have the gasket have read the manual several times and am just waiting for the weather to be agreeable for this work. just step back inside from trying to find the 750 ohm resistor that controls the retard. the manual indicated it was beneath the air cleaner. wasn't but that is another post, unless there is a wiz who could point me to it.

anyway when i removed the air cleaner i noticed that it has several teaspoons of oil in it. the element was replace the 1st of feb so i know it wasn't there then. this car has been inspected by a mercedes dealer, new buyer inspection. that is why i am replacing the valve cover gasket and head gasket. they indicated a leak in the cover and head.

there is oil all over everything and in the air cleaner. what could be causeing that? there is always an oil spot on the ground when i park the car. i also need to add oil every 500 miles or so. i believe this is the valve cover and head leak. but what about the oil on the upper surfaces and in the air cleaner.

is there anyone out ther who might be able to indicate why this is happening?

thank you very much

vincent