i recently bought a well kept 01 325xi wagon with a manual, i bought it knowing the valve cover was seeping and since replaced it however there is still a "hot" burning smell after traveling on the highway. I don't think it's engine oil cause it has a different smell and doesn't come in the cab while driving. the odor seems to be stronger under the car, i thought it could be the clutch so i tried to get the clutch to slip under WOT on the highway at around 3k-4k but didn't notice the tach jump. the clutch seems to bite strong. any ideas?