I'm getting ready to buy a 350SDL. It seems to be in great shape but I don't know much about that model. I now own a 300SD. Anybody have any feelings about the 350SDL or can give me any pros or cons about this particular model?
Any information would be appreaciated.

Thank You,
John

Due to design defects, these engines have a history of pre-mature failure.

See this site for more info: http://www.mbz.org/complaints/350D/

Run away! Run away! (to quote Monty Python)

Seriously, this is by far the worst engine MB has ever built. Very significant numbers of these things blew up well before 100K miles. Search the archives here, it's quite well documented. I think there was even an occurence in the last month or two.

It generally begins with excessive oil consumption - this is the cylinder walls becoming ovalized. Then the idle gets a bit rough. Then the power starts to decline. Then a rod lets go and blows a hole in the engine block.

It costs ~$10K to repair.

MB came out with revised engine components which are reputed to solve the problem. If the engine in this car has been rebuilt and it has the improved mechanicals, then consider buying it. Otherwise walk away, go find a nice 420SEL or 560SEL if you've got to have a 126. Either will be much less expensive to own.

- Jim

On the other hand, and I might add a small percentage of the other hands, some 350s seem to do OK.

My 1991 SDL has 125K and runs extremely well with no oil burning between changes. I use synthetics.

My understanding of the "problem" is that there is no "onset indicator" at all. It just happens one day ... my understanding, also, is that it normally "happens" earlier than six digit mileage, but does afterwards, as well. Big issue is that it appears to happen to all of them before it would have happened to the unbored and stroked 3 liters.

I am hoping to be surprised by the longevity of mine.

Fingers crossed.

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg

good for you George...you are probably one of those guys that will never have any problems....I have seen a '90 with 225 miles and no problems and a 93 with 240K and no probs.....I was told that some people think that the cars that were run with mostly highway miles fared much better than a city driven car...who knows?.......as for the purchase of one I would have it throughly checked out by an MB dealer or a qualified tech who knows the danger signs on this engine...trust me I know ...mine had started to burn a quart of oil every 150 miles ......
My tech that did the new engine install said MB had changed many parts in the new engine....and the regional MB rep told me he had never heard of any problems nor paid any warranty claims on the replacement engines

good luck

Warren
1992 300SD 126K
Columbus Ohio

What's the warranty on a replacement engine? Even the derelict original ones lasted 100,000 miles or so.

Sixto
91 300SE
81 300SD

I hear there is a stciker that used to be on the 3.5 dieel motors.

"Please note that qulaity of the 3.5 diesel motor is not a representation of any quality MBZ product. Failure to buy any other MBZ aside from the 3.5 diesel may resilt in shortened engine life, bent rods and spending lots of money after MBZ gives you another recalled motor."

Just kidding. Seriously, it is just a fact that this motor has a HIGH failure rate.

I agree. If you like the 126 body and a diesel, you should really consider a 86 or 87 300SDL.. they look exactly the same as the 350SDL but with a proven good motor, and almost as much power. I think 148hp compared to 155? My 300SDL has 246K, I have driven them with 350K, seen one with 502K and someone just recenly posted a picture of one with an unbeliveable 835K miles., original engine!!

Definately stay away from any 3.5L I6 powered mercedes (350SD, SDL, S350, S300), nothing but trouble.

A couple of points need to made here......first of all not everyone had problems with this engine.....and most of the ones that failed (that I have seen) did so before 100K....many with less than 60K

In regards to buying a car with this engine....great car...an improvement in driveability over the 86-87 SDL as well as fuel mileage...as well as dual airbags(in many cases) and an updated interior.......if anyone is looking at these I would suggest that you buy one that has been dealer serviced its whole life ....the dealers seemed to have caught problems with this car before it got to the danger zone in many cases and knew how to fix it.....I think there were many technical bulletions that were issued on this car that only dealers must have seen....by the way the warranty on the replacement long block is 48mo50K parts and labor at any MB dealer......but I have seen MB give goodwill on original engines up to about 75-80K regardless of the age of the car

Warren
1992 300SD 126K
Columbus Ohio

I appreciate the help; it's differently given me something to think about. The car I'm referring to is a 1990 350SDL. The engine is currently being rebuilt and the price will be about 8500.00. Nobody said much about the rebuilt engine. Would this now be a good buy?

How much is this car if you dont mind me asking.. with a rebuilt engine I may even consider one.. but I have heard of the rebuilt engines blowing up after a few hundred miles because some moron didnt set something right or had a few extra parts when he was done..

John

I guess thats another case to be very careful about who is doing the rebuild....the part I don't et on the rebuild is usually its only about 1500 less than a complete MB rebuilt longblock after labor is factored in......so if someone was paying why go rebuild?.....1 year(at most) warranty versues 48mo 50K parts and labor at any MB dealer in the US....seems like a no brainer to me...plus you et the updated head....and tons of updated parts with the MB rebuilt unit...as far as $8500 goes it would depend on the mileage , condition and who was doing the rebuild...because who wants to be in that situation again.....if a dealer does the work...go for it...my rationale is go after MB if the dealer does not follow through...otherwise if you have problems ..you are on your own...but compared to the SD you now own you will notice a world's of difference in power,smoothness and amenities

good luck

Warren
1992 300SD 126K
Columbus Ohio

"It generally begins with excessive oil consumption - this is the cylinder walls becoming ovalized. Then the idle gets a bit rough. Then the power starts to decline. Then a rod lets go and blows a hole in the engine block. "............from an earlier post


I guess I have a stupid question here.......who keeps driving the car after they notice these probs....?.....I mean my car was burning oil at a quart every 150 miles and blowing clouds of smoke.....how could I have missed that?......it seems that there are those that did drive until the bent rods that were causing the problem came throught the block!!.....I guess its one of those situations similiar to brakes...you have those who have their pads changed when the light comes on etc...and those who drive until the last of the metal is grinding....in the end who spends more money?.....

Warren
300SD 126K
Columbus Ohio

Dude, people, atleast around where I live, treat these cars (and most cars) like crap. I see TONS of 123's and 126's with the wheels (all 4) BLACK from brake dust, dirty, leaking oil all over, lucky if the drivers window works. Fact is, the average guy who dont really know alot about cars or just plain dont care and use it get to work everyday will drive it into the ground. Take a look at this gem.. perfect example..



Oops, sorry for the rant.

I love the pic. Perfect example.. fact is, 126 cars are getting pretty cheap these days. The nice ones still command a high price, though.

__________________
2003 S500 Black/Charcoal
1990 560SEL 61k Arctic White/Grey

SOLD:
1988 420SEL Black/Palomino Sold @ 85k
1987 420SEL Midnight Blue/Grey
1986 420SEL Diamond Blue/Grey
1983 380SEL Champagne/Palomino