Someone did some research and concluded that oil gets into the combustion chambers through leaky turbo seals and/or the EGR valve and causes one thing then another then the rods bend. It was a complex explanation that made sense when I read it. Not before and not since

Sixto
95 S420
87 300SDL

See Benzmac's post near the bottom of this thread.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Interesting! I guess the best thing then is to disable the EGR so that you don't get into that situation. Were there any other things that could cause the rods to bend?

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

thats easier said than done on anything newer than 89.

my dad's got a 350SD, its been rebuilt twice, first by MB at about 40k miles (the timing chain failed, not the rods) but they didnt quite do it right, so it was rebuilt again by and indie mechanic at about 100k miles and its perfect.

since then hes had to replace the turbo, i think its got about 140k miles now.

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1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

Urban legend in the middle '90s attributed bent rods to "Deck
height" (for urban legends =/substitute:Montvale, N.J.)

Recently, Master forensic mechanics have promulgated the
theory: Glow plug failure on one or more cylinders leads to
excess unburnable fuel and HYDROLOCK.

Interesting reading, thanks all. I guess there are several ways to "skin THIS cat" so to speak...the hydrolocking explanation makes a lot of sense, I can't really picture what the other was mentioning about the egr, but interesting nonetheless...I'm definately going to look more closely next time I come across one.

Hmmmm...I still want one though.

How about poor design and not enough testing by MB.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Whatever the case, be it internal design flaw, or external device failure, MB does not and WILL not stand behind their product as of now.

To me, that speaks something of the brand.

__________________
1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

Prior to purchasing my new to me 91 350sd I asked 2 indies and 2 different MB shops about the bad engines, and got 4 different answers. hyrolock, poor design, excessive back pressure by the ceramic exhaust pipe, etc.

Then I read the 'report' on the 603 engine posted somewhere else. They say 40% fail, so 60% last. that's better than lots of things in life.

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71 220D 169K wrecked
83 240D 118K sweet 4 speed
91 350SDL (one of the 60% good engines) 156K
84 300d (loaner to my sister) 189K
79 300SD (partswagen)
86 420SEL partswagen
70 220d (partswagen)
68 280s GASSER!!! under construction now
85 300sd 310K miles winter beater car retired
93 300d 2.5 turbo 168K wife's car
83 280SL euro 5 speed 155K
69 250S newest project 54K

It sounds like M-B is becoming more like an American brand.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I have two 350's, a 91 350SD and a 90 350SDL. I purchased the 350SD from the previous owner with 200,000 miles on it. He was one of these guys who did absolutely NO service. I have the service history on the car, and the most expensive thing it had done to it was the idler pulley and shock. To me it showed that someone could just drive one of them into the ground and it still keep going.

That being said, the engine is excellent. It had a couple of tired injectors, but no issues. Burns no oil, had some oil leaks that I fixed. Evidently, this must be one of them with a "good" engine. Course I went through the car and did a lot of maintenance to get it up to being my daily driver. After owning this car, and driving a couple of other 350s, I decided to not be so afraid of the engines.

Then couple weeks ago I grabbed a 90 350SDL with only 51,000 miles on it. Elderly gentleman owned it. This will be my keeper, course with my luck this one will develop some issues before it gets to 200,000 miles.

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1991 350SD 265,000 miles
1981 300D 320,000 miles

1990 350SDL 144,000 miles (wrecked)
1991 350SD 225,000 miles (sold)
1985 300D 113,000 (sold)
1987 300SDL 183,000 (sold)
1984 300D 360,000 (sold)

...and here I am posting two and a half years later!

I just bought a '91 350SD with 213,000 miles (now 214,000) and I love the car! It drives really great, is super fast and powerful, and is a real joy to drive!

I'm trying to find and follow all the tips and advice to keep this car running a long time, so please feel free to let me know if you have any recommendation (other than get rid of the car - I've already heard that one enough from the critics!)

Hey Benster-
If you want a short article about the 350 Sd engine, it's more of the same as the others have stated. Am I allowed to put another website name on this thread, moderator?
Here goes nothin' MBZ.org you might already be familiar with this.
Under the Info category there is "complaints" . Click on that and it leads you straight to 350 SD article.
I stayed clear of the alleged years of this model because I didn't want to take a chance, becoming a first time MBZ owner just to be riddled with $$ problems. My other cars were trouble free and I want to keep the good Kar-ma going. Hope that helps.
Frankie
1984 300 SD rookie