ronvader

Try the capscrews that hold down the rear valve cover. They do come loose on some cars. Happened to me. Mine were loose enough to turn with my fingers. After I tightened them, I had the engine washed and shampooed. No more problems.

I had the same problem for two years, with oil leaking at rear of engine. My ES300 has 300000km on it, runs well, doesn't use oil internally, but oil was burning on the hot exhaust pipe as it passes under and to the rear of the engine. My Lexus dealership failed to diagnose the problem. Two other (general mechanic) shops couldn't find it. A local Pennzoil Oil Change Service Center told me it looked like a drive shaft seal was leaking bad. Main symptom was a very annoying burning stinky oil smell coming in the vents when at rest after car warmed up. No real oil stains on ground. This had been occurring over a 2 year period and was driving me nuts. Finally I got fed up and took the following steps; a) Got really mad and fed-up! b) Drove front wheels up onto a high curb so I could crawl underneath for a look with a flashlight. Looked around from topside as well, using a portable mirror. I did this after dark so I could see better (strange as it sounds). I confirmed clean oil wetness originating from rear edge of rear valve cover, and running down onto exhaust pipe. I tested and found several of the valve cover capscrews were loose enough to turn using my fingers. Made sense, oil pools there somewhat during operation, then drains back down into crankcase after shutdown (explaining the lack of driveway stains). c) Got a combination spanner (10mm A/F) and a bright flashlight. Tightened each of the capscrews by hand. I had to be a bit of a contortionist, but fortunately I was still angry (and stubborn). I did manage to get at and tightened them all d) Took car to detailing shop, had the engine & area professionally washed & cleaned. I haven't had any problems since. Not this type of problem anyway. Hope this helps someone...