It's not normal to use a quart every 750 mi, and adding more is just throwing money out the exhaust pipe. My 86 300E with 120K mi. uses less than a quart in 3000 mi. In addition, it will create carbon deposits on your valves, pistons and combustion chambers, as well as fouling your spark plugs, catalytic converter and oxygen sensor. Sounds like your valve guide seals are worn, allowing oil to be drawn into the combustion chamber. This appears to be a problem on some cars, usually at about 80-100k mi. How many miles are on your car?
Replacing them isn't that difficult if you're mechanically inclined and can beg, borrow or rent the right valve spring compressor. Otherwise, here's a quote from Steve Brotherton (stevebfl) of Continental Imports in Gainesville, FL:
"The job is 4 hours labor and less than $20 for seals. If you figure that the V/C gasket should be replaced about every 100k, then the extra work to systematically maintain the seals at the same time would only be 3 extra hours labor and less than 20 for seals."
Another possibility would be an oil leak. Get under the car and remove the noise shield that's held on with 6 sheet metal screws. Put a large, clean piece of cardboard under the car right after you drive home and leave the engine running for about 5 or 10 minutes. Look for drips and detrmine if their originating from the front, middle or back of the engine and see if you can track it down. Sometimes it can help to degrease the engine thoroughly first, although look for obvious signs of fresh leakage before you wash away the evidence.
The engine running hot is a totally unrelated problem. It would be good to have a little more information as to the specifics of when and under what conditions it runs hot, as well as how hot. It could be anything from a thermostat that's not operating properly to a fan that's not coming on when it's supposed to, to a corroded, gunked up radiator that can't cool effectively.
Can't help on the trans problem. Automatic Transmissions are like Black Magic boxes to me.
Last edited by Phalcon51; 08-27-2003 at 05:17 AM.