Hi, I've got a '78 240D with 85,000 miles on it. I just bought it about six months ago. It always starts, even in 17 degree weather, but it burns oil, like a quart every thousand miles. It has low power, but after pumpimg the brake in neutral, it drives for a minute the way it's supposed to....it will pretty easily make it to 70 or 80 on the highway.
One mechanic told me that it needs a new motor and fuel injector pump (or new rings).
Then a second mechanic, who worked for Mercedes for 12 years, told me that the engine is good, but it's the transmission, which he doesn't do, but that it has low power because the engine is working extra hard to make up for the problem with the transmission.
Now a third mechanic, our neighbor, looked at it and said the transmission's fine, and it's the rings.
Any thoughts? Ideas? The former Mercedes mechanic said to take it to someone we trust and have them look at the tranny, but we don't have a trusted mechanic in New York. Thanks for any input.

 

A compression test would confirm stuck/worn out rings. Try an oil additive that claims to free up stuck rings. A simple test is to remove the oil filler cap and just rest it on the valve cover hole. If it blows off or jumps around alot then there is excess blowby pointing to stuck rings. I think stuck because of the very low mileage for the year.