Aloha from Maui !
I love my 88 300TD BUT ! Can't live without using biodiesel.There's 91 300SDL with 180kmiles on clock for sale. Here on forum i've learned that it's 603.970 is "worst diesel engine made by mercedes" so my questions are:
-what are chances that it will keep running?
-what shall i check when i will go to see it on saturday?
Thank you for your time
Petr

Check the many forum threads on this motor,under 350SD, 350SDL, and rod bender...The 350 diesel is unfortunatgely known as the "rod bender" motor and is generally regarded as Mercedes' worst diesel effort, usually to be avoided. (Though some people have reported it as giving them no trouble however)

The humidity in Hi. can cause rust so check for it, and these cars have problematic air conditioners, so be sure it blows cold, and try to get service records and stamped books, if possible, and look for evidence of prior accidents or bodywork.

There's a useful and rather long buyers guide for the W126 models (sedans and coupes) which I co-authored with Satish Tummala back in 1998. It caters primarily to the 560 coupe model, but can be applied to a diesel sedan as you are considering. Click www.mbcoupes.com (buyers guide.)

The W126 models are probably thin on the ground in Hawaii, though.

__________________
1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...

1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)

The chances of keeping it running are 100%, provided you have an $8K reserve account if the engine goes south.

The vehicle has a multitude of things to check to determine if it's got 180K on the clock with no maintenance or repairs or if it's got $10K of maintenance over the years. This is best done by an independent mechanic who is familiar with the vehicles. It's not possible to go and kick the tires and make any kind of proper judgment about it, unless you are very familiar with that specific vehicle.

There is nothing that can be checked to determine if the engine already has a bent connecting rod. It will idle and drive perfectly fine, unless it's already an advanced case and the idle has deteriorated due to poor compression in the affected cylinder.

Figure your odds at 1:3 that the engine will develop a bent rod at some point in its life.

Why can't you run biodiesel in the 300TD? Is it an 88 or 87?

Sixto
93 300SD

At this point a lot of the 3.5 litre equiped cars are going to be for sale. As long as one factors in putting a short block 3 litre in you should be safe. If the 3.5 litre lives fine if not you have allowed for it. A not unreasonable barganing point at time of purchase. If you see the lack of material between the bores on the 3.5 engine versus the 3 litre it gives some insite to the probable causitive factor. Or perhaps just the contributing lack of strength compared to the 3 litre. If you cannot factor it into the deal I would purchase a car with perhaps a better engine track record. Just some observations as to how I visulise a car with that particular engine. Others opinions will totally vary and thats what makes the world go round. As mentioned the balance of the car should be really checked out by somebody with extensive knowledge of this model anyways.

Would it be possible to insert sleeves into a 350 block to bring it back to a 300?

__________________
http://i284.photobucket.com/albums/l...aman/Fleet.jpg

Peach Parts W124.128 User Group.

80 280SL
85 300SD
87 300TD
92 300D 2.5 Turbo
92 300TE 4Matic

Even if you did sleeve it down to a 300, what have you gained? Less horsepower with the same rod issue as before, right?

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Not if you get a set of 300 rods. Granted you will have less HP, but at least the issues of failure might be mitigated. I don't have this as a problem myself - just wondering.

__________________
http://i284.photobucket.com/albums/l...aman/Fleet.jpg

Peach Parts W124.128 User Group.

80 280SL
85 300SD
87 300TD
92 300D 2.5 Turbo
92 300TE 4Matic

Were you thinking of moving the 3.0 reciprocating assembly into the 3.5 bock? Much easier and cheaper to start with a running 3.0 block, If it comes out of a running car, it's very likely a useable block. Swap the 17 head of the 350 if that makes you feel better but no need to touch the bottom end.

If you're thinking of using 3.0 pistons and rods with the 3.5 crank, it won't work - the pistons will smack into the head before the crank reaches TDC.

Sixto
87 300D

One of the theories advanced as to WHY the "rod-bender" bends rods is that coolant, water, or oil leaks into one or more cylinders and causes the engine to hydro-lock, thus bending a rod. I do not advance this hypothesis, just mention it as one possibility. If that were to be the case, neither sleeving nor stronger rods would help.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Nobody knows the rod-bending cause. Unless MB comes out and tells us, anything that is said about the cause is just guessing.

That's a widely accepted cause in the generic sense. I have two bent 3.5 rods that came off an engine that didn't have coolant leaks into the cylinders. It did have an oil leak into one of the cylinders

Sixto
87 300D

Then what makes the 3.5L special that it sucks in oil/water/coolant to bend rods and the 3.0L does not?

There is a 1995 S350D on ebay:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=020&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=300133595669&rd=1&rd=1

They claim that MB corrected the weak rod issue after 1994. Here is their explanation. Have you heard about that? (They want over $17K for the car for this reason...)

__________________
1974 240D, 125K mi, B100 now, SOLD
1980 300TD, 115K mi, 4-speed stick, roll-up windows, greasecar with two tank conversion (daily driver)
1985 300D, 220K miles, greasecar with two tank conversion, SOLD
1993 300D 2.5turbo, 158K miles, green/tan, B20-B50

That's just a selling point to get it selling faster. Of course he is going to describe his car as perfect.