We own two 300d's and love them especially here in California---no need for a smog test!! Our 84 300td's (201,000 miles) engine is strong and does not burn a drop of oil. Our 79 300d(190,000 miles) burns 3/4 of a qt. every 400 miles. It has been doing this since I bought it from the original owner almost 5 years ago. I've had a compression test done and the mec. said that each cylinder tested out around 360?? My current mec. said to continue to drive it and continue to put in oil when needed. At some point he says I'll need to overhall the engine (when it won't start). Should I continue to drive it as I have been. Even though I put REDLINE in at each fill-up, it smokes alot. One advantage, nobody tailgates me! Any help would be appreciated.

Gregg,

I (and my daughter) certainly understand the frustration involved when driving an oil burner.

The good news is that with a tired diesel engine, there is no other downside except the fact that you have to add oil all the time. In the case of a gas engine, when tired, it will foul spark plugs, burn valves and other ills that will demand overhaul.

With a diesel engine these problems don't exist. In fact the oil is burned, making for expensive fuel. As long as you can carry enough oil with you to get where you're going, and the engine will start to get there, you can keep driving a diesel.

Your engine sounds a bit unique. Since it has very good compression, I expect that valve guides and seals would bring it up to snuff. The bores and rings must be in good shape to produce this kind of compression. You might consider pulling the head and doing a valve job including new guides.

Best of luck,

Although my 240D burns a heck of a lot of oil, it also has some small leaks. I've heard that heavy Diesel oil shipped from germany is better because it reduces the engine's tendency to leak. I am wondering if all Diesels leak Oil or should I take the engine apart... check gaskets and the like with the mission of stopping "the small drip"?

I had an old 300D non turbo wagon with the same engine trouble. It was an oil burner. The compression showed good.

I pulled the engine and disassembled it. What I found surprised me, but after I talked with other techs, I found it to be normal.

The engine cylinder walls were ridged at the top indicating wear.

I re-sleeved the engine and installed new rings and performed a valve job. The engine is now running on the 5 year perfect. I would suspect that at another 200k or so, it will be needed again.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS