I too have that burning oil smell on my '03 with M54 engine. I have found oil beneath the oil filter housing, so I suspect the oil filter housing gasket, which I've ordered thru the plant. HOWEVER... can oil leaking on that side of the block really cause that burning smell? I would expect the smell to be caused by oil burning on the exhaust manifold, but can find no signs of oil leaking on that side of the engine. I replaced the valve cover gasket last weekend, suspecting oil was leaking there (the car has approx. 110K miles).

Could oil leaking from the hose between the oil separator valve and the dipstick tube be finding its way to some part of the exhaust and burning off then? I have an OSV and the 4 hoses to install, but when I got started with the replacement I ran into difficulty removing the wire junction block, and gave up on getting to the OSV... (I've since found a nice diagram on TIS that shows me exactly where the last bolt is to remove the block)

Maybe I'm crazy, or maybe just a lil too proud of my E53, but I'm actually enjoying all this... sick, I know...

As always, any and all comments or suggestions are welcome!