MATT300SD

Which engine is better? ...The 5 cylinder Turbo Diesel in the 300SD or the 6 cylinder in the 300SDL?

Which one lasts longer, costs less to operate and maintain, and gets better MPG? Which one is better able to handle SVO/WVO/Biodiesel with or without any modifications?

-MATT300SD

jhutton

i have heard that the 3.0 i5 is the most reliable and having owned one find it very reliable parts are not expensive and i can do most of the work myself, 300K and still great oil presure and running great just replacing seals and gaskets to reduce oil leaks

Untertürkheim

You cannot run properly made biodiesel in either as long as rubber and plastic parts are replaced with pieces that will tolerate biodiesel. SVO and WVO are never a good idea, period.

Both engines will stretch the timing chain at the same rate, mostly determined by the quality of oil used and the frequency of service. Air and fuel filters have the same replacement schedule as does every lubricant. The older I5 requires a valve clearance adjustment every 10-15k miles, but this is very easy, and provides a perfect opportunity to check timing chain stretch.

The newer engine is more powerful and should be more efficient. The newer I6 cylinder heads may crack if the car was neglected.

Any Mercedes is the wrong choice if you do not plan on keeping a high level of maintainance.

MATT300SD

That's why I love old cars and especially the W126's because they're so simple. Modern cars are too complicated with all the computer crap and electronic stuff.

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Thanks for the advice on the bio-fuel stuff.

hineywineries

[QUOTE=MATT300SD;2528439]That's why I love old cars and especially the W126's because they're so simple. Modern cars are too complicated with all the computer crap and electronic stuff. Hey,
It isn't just cars anymore. After 30 years of being a factory trained MB mechanic, the last thing I want to do in my spare time is tinker with a car. I'm a fairly accomplished self taught cook which is how I spend my spare time. I decided it was time to move up to a professional stove. I settled on a Viking. I was ready to shell out the $3400 US when I talked to a Viking repairman. He said they were a technology nightmare. He said get one 10 to 15 years old like his wife has. I found a pre nightmare 7 year old unit and even saved money.

About the choice between a 5 and 6 cyl diesel, I have no experience with the 6 cyl. I have owned a dozen or so turbo 5 cyl models. I've found it to be a bullet proof engine. Some are concerned about the timing chain, but the concensus of MB mechanics is that MB only had problems with V8s. The OM 615, Om616, Om 617, and the m103 engines just don't have chain problems. The one thing that will kill a diesel engine is short distance driving. I have an 83 turbo wagon with 360,000 miles on it, and the engine is in excellent shape, because we used to commute with it. I don't commute any more and my wife takes the backroads to work in Napa which sucks for a diesel, so she drives a 97 SL320. She smokes that winding road with that thing. I've gotten rid of all the diesels and gone back to gas. This spring I plan to convert my wagon and diesel truck to vegetable oil. Last year I got to work side by side with a representative from Elsbeth in Germany converting diesels. We had two work shops for two days so I think I'm up to speed. I just need the time.

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kellerboy

hineywineries is Right they are bullet proof engine for sure .and if you tune the timeing on the pump and do some extra`s.then you have power like a gas engine.

hineywineries

As another interesting point, the 4 cyl diesel, the 5 cyl naturally aspirated, and the 5 cyl turbo take the same timing chain.