Hello all! Im a Boxer owner and now a 365 queen owner. (sucker) My beloved 365 has 53K miles on it and Ive read the articles on oil burning issues. However, my car goes through 1 quart for every 2 hours or so of "spirited" driving. Is this acceptable? When is a top end rebuild necessary? Many thanks, John
To your knowledge, has the engine ever been completely/thoroughly rebuilt ? If not, with that mileage and apparent problem, you might want to consider doing it all and doing it right, instead of just "top end"
Could be a number of things, bad valve stem seals especially on inlet valves, can cause a lot of oil burn that is not always visible from tailpipe smoke. If the oil burn is correlated to a lot of high RPM then it could well be the rings. Are there ash deposits on the spark plugs? And is the engine otherwise leak-free? Leak-down test? These and a good number of other things to check before tearing her down.
Hi John,I would think that burning that much oil would create a significant amount of smoke.If so OK but look hard for leaks that show up when the revs are up and make sure your level is correct and your additions are not overfilling. Mike
If you do not have a great deal of smoke, it's possible that you blow it out the crankshaft seals. Clean the engine and run it again and look for leaks. john
Does anyone know how many pints are represented between the MAX and MIN indicators on the dipstick? Thanks John
I posted this recently in the other current oil consumption thread. Perhaps it will give you some insight. http://www.amsoil.com/techservicesbulletin/MotorOil/TSB%20MO-2004-04-03%20Oil%20Consumption.pdf
I'd be concerned if that much oil was consumed during 650 mile drive. As there's potentially numerous reasons, it's tim to quit attempting interweb analysis and start actual work to figure out what is the cause. And unless you have 100% confidence going through the diagnostic process yourself, find a mechanic/shop that has experience and is familiar with this type of cars/engines.
I think you know by now that you are using too much oil. The next question would be what to do next? If it's not leaking the oil profusely then its burning it (assuming it's not it's going into the radiator) so it means rings or valves need attention. I would start by doing a compression and leak down test to indicate weather it's a top end or bottom end problem. Maybe you just need head work. My car (late 330 GTC) was using similar amounts of oil and the car was smoking like crazy, especially at idle (high vacuum). There was even oil dripping from the exhaust manifolds after shut down. When I did the tear down I expected to see very worn valve guides but it turned out to be the valve guide seals. The engine was way overdue for an overhaul anyway at 78k miles, so everything needed attention.
Thanks for the advice! The car has been sitting for awhile as most do. Not much smoke at idle, so Im guessing the top end was done at some point. Im going to drive it another 300 miles (adding oil) to see if consumption goes down. No external leaks that I can see, but on the highway if you go up to 6000 rpm and let off the throttle, there is some real smoke for sure. Do rings ever come back or reseal after some hard driving? JWW
Marvel Oil in the fuel will not hurt anything, and may help free any stuck rings. Best thing is to put some miles on it before making an expensive decision.