In Reply to: Re: oil loss on cruising????? posted by Les on September 14, 1999 at 15:28:31:
: The higher revs produce greater pressures and you are probably blowing your oil out somewhere because of worn seals or bearings.
This is not completely accurate. Your oil may move around more at higher RPMs, but the oil pressure is lower. It only increases under load and should be lowest when idling and cruising.
The problem could be a leak from any number of gaskets that only develop on extended trips after the engine has reached a certain temperature range. You may not get the engine hot enough tooling around town, so the leak never springs then. Drive at 70 MPH for a few hours and everything starts to soften up in the engine compartment. I myself have blown my exhaust manifold gaskets driving one particular trip from Atlanta to D.C. nonstop in my 535i.
Or you could be burning/blowing oil, which would just be aggravated at higher speeds. On your next long trip, floor the accelerator a few times and watch you mirrors (or have someone follow and observe you). If you see lots of blue smoke, that's oil you're burning. That means it could be piston rings, valves, etc.
90 535iM, sharked, CCA