From: C. E. White on 26 Oct 2009 09:10
"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
> I suppose oil could leak into the combustion chambers (around the
> valve seals) slow enough that it could burn cleanly enough that
> there was no trace on the rear-facing panels, but if that was the
> case you should not be using a quart every three hundred miles.
> Another route for the oil to take is past the rings, but the rate
> that you have to replace the oil indicates there ought to be visible
> signs of where it's going.
A quart every 300 miles is not likely to show up in the exhaust until
the catalytic convertor fails. Unfortunately, if that much oil is
being burned inthe engine, the converter will eventually fail.
If the engine has been decently cared for (regular oil changes 3K to
5k depending on conditions) and not abused, then I doubt the rings are
the problem. If the engine is not leaking oil, then I'd look at the
valve guide seals as the source of the loss. For a vehicle of that
age, it is possible that the seals have hardened and are not doing a
good job of keeping oil out of the combustion chamber. Before taking
it to the shop, it might be worth trying one of the high mileage oils
(like Valvoline MaxLife). It is also possible that sludge is
preventing oil from properly draining from the head back to the oil
pan. This can lead to excessive oil loss through the valve guides. I'd
suggest taking a good look in the oil fill port. If you see a lot of
grung, I'd suggest pulling the valve cover to take a look. A good
independent mechanic should be able to diagnose the problem and
recommend solutions. I'd be surprised it a total engine rebuild was
necessary. Almost any engine can make 200,000 today as long as it is
decently cared for.