1995 e320 occasional cabin smell

[sasjzl]

Hi all,
I have a 1995 E320 that has an intermittent smell like oil inside the cabin. It is very strange because it is only occasionally there and I cannot find any pattern to its appearance. I did have a very definite oil smell before I replaced the head gasket because of the typical leak but that is no longer leaking. The oil level has been normal and there is some oil on the bottom of the engine but nothing like there used to be with the old leaky gasket. I get out of the car and even if I just smelled it I cannot smell anything after opening up the engine compartment. I do see alot of leaves and other organic stuff all over the area where I think the cabin air gets sucked in. The two vents just below the wiper motor area. I am going to blow all that stuff out to see if it makes a difference but this smells like a fluid and I do not see any fluids leaking anywhere near that vent. Are there other input vents on the firewall? When I do smell it it seems to be coming in with or without the a/c air.

Any thoughts more than welcome.

Thanks very much,
Jim Lee