I am picking up on Wednesday, a 1991 Merc 350sd w/ 88k original miles. The owner is the nephew of a Doctor who'd bought it new in 1991. It was a Florida car and driven daily for some years. The Nephew drought the car to PA and proceeded to drive it daily for some months. He tells me now the car is leaking three different fluids: Diesel, power steering and tranny. While the leaks are not alot, they need addressed. Also the car is in need of struts. He tells me that he believes that the climate changes contributed to seal fatigue and thus the leaks.... Well here are a couple questions for you maniacs:

#1... How can I tell if the motor was ever replaced by a mb dealer under warranty? Are there numbers on the head and block that I should investigate?
#2... Do you buy the leak explanation, and are there any common causes of these issues?
#3... What shocks/struts are recommended for this car? I see Koni's on Ebay, and know bilsteins are good. Suggestions?
#4... What else should I look out for, ie rod bender tell tale signs, maint issues?
#5... What is this car worth in this condition?

#6... Does anyone have any good wheels that fit this car for-sale?

Ask him how much oil it uses between oil changes.

That is the problem with owning one of these rod benders. It is fine, and darn nice, right up until the rod decides to pull a Clinton......{anyone????}
Bilsteins are the way to go, shock wise.
These cars do mark their spot. Power steering leak is usually from a hose, and is easily replaceable.
Oil leaks have many sources.
Hope the tranny leak is the pan gasket or from the banjo lines.
Remember, these cars are always going "tick, tick,tick....."
And it isn't the clock...........

Maniacs?????

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Swaartz,

With all the information on this website about the problems with the 350 engines, I don't know why you'd even consider touching that car with a 10 foot pole (with the exception of having a good six cyl 300 laying around as an exchange).

I think most of you whom are considering these cars are thinking "maybe I'll get lucky and not have the problems".

Roll the dice buddy, do ya feel lucky? Well do ya?

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

Well a 300SDL motor drop in as a replacement motor or is there a different 300 motor that will?

Nice car, enjoy it.

As to the shocks, Bilstein Comforts are just about the best for the W126 sedan. They provide the kind of ride you would expect, comfortable but stiff enough for a European car. They run about $60-$70 each.

All these cars leak a bit, you need to clean up the engine and figure out where the leaks are coming from. Its an old Mercedes thing, you fix the leaks that bother you or make a mess and ignore others.

The power steering is probably the return lines which rot, or it could be the shaft seal on the gearbox. Both are pretty common and not a big deal.

As for the engine, change the oil when you get it and fill it to the half way mark on the dipstick, about 7.5 quarts on mine. Then keep an eye on it, a tight 603 should burn nothing after 3k-5k miles. If you are burning a quart every few hundred you have a rod problem. A quart every 3k and your fine. These engines do give a lot of warning if you know what to look for, oil consumption will increase to the point that it won't run. So keep an eye on oil consumption.

As for wheels Tirerack offers a large selection, I think the updated 8 holes look rather nice. Or you can go with something like a set of period AMG Penta's.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

All good info guys... This car was definitely babied. As far as why would I go there? The car is well worth what the man is asking for it. If I had to re-build one of these engines, there should be plenty of blocks out there, correct? Could they be punched and sleeved? At the end of the day, a car with good history and low mileage IS desirable to me. Plus, this car looks better imo than a 300sd. Lastly, has anyone ever polled 350sd or 350sdl rod bender owners for mileage when it went to hell? Low mileage cars still may have a chance of rectifying before the catastrophic issue, correct?



I also heard that MB dealers replaced some of these motors. How could you tell if it has occured? Thanks

Some dealers won't release the repair records they did,others might.

See if you can get a Mercedes dealer to run (and decode) the MB net Vehicle Master Inquiry, it shows all repairs made under warranty.

It might NOT show repairs made under a "secret" warranty if the motor was replaced or rebuilt under one of those.

Still it's would be worth a shot to at least try for one and see what shows up.

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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)

No this is a pretty rare engine, if it blows you are looking at at least $4k for a short block. Long blocks run about $6k, and complete crate motors about $12k. Decent used ones are hard to find, and expect to pay $1k-$2k for one. It can be difficult to find a machine shop that can properly rebuild a MB engine, these are not 350 Chevy's and if rebuilt like one become boat anchors.

They only made about 2,300, 350SD's. The 603's are not that commen in 3L and 3.5L form, so some 603 parts cost a lot more, like the radiator and oil cooler. Any parts that are not 603 specific are pretty cheap and easy to come by.

Personaly I like the 350SD enough that the potential of having to replace the engine wouldn't stop me from getting one.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Thank's for the info..... I was really trying to find a 97-99 E300td, but this car just is too good to pass up. If I fix these leaks, what is this car worth? Again, she's beige w/ 88k miles. Records are pretty intact..... Beautiful condition. Even as she leaked, she's been garage kept!

If this car's engine is still intact, could the bottom end be re-worked, ie new rods? to fix the 'rod bender?'

I'm curios: is there absolutly nothing one can do to prevent a bent rod in a 350? It's very hard to believe that MB put some crap like this on the market.

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'99 S420, 155k
'91 VW Vanagon GL, 150k
'85 VW Vanagon GL, 120k
'82 VW Westy, aircooled, 165k

AFAIK their is no way to prevent it, their are some good threads on this subject in the archives.

You could pull it apart and change the rods out, but why pay for a rebuild that you may never have to do? Some of these engines run 400k+ miles without this issue.


If that car is really in mint shape you could probably get $12k-$14k for it, but thats a guess I have not been keeping an eye on the market lately.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

There are some good 350SDL's out there, I have one.

I am the original owner of one that now has 186K miles on it. I have not had any major engine issues and it still runs great.

My engine was produced in December 1990, don't know if that makes any difference or not.

These can be incredibly fine cars if you get a good one.

Enjoy.

I actually own one of these "rod benders". If the car has 88k on it with no problems your probably ok for another 100k anyway. Don't try to hyper tune it-remember it is a diesel not a 426 Hemi. In FL where it stays warm you should be ok. I had some oil in water at 200k and replaced the head gasket. The machine shop checked the head and it was perfect. I checked the clyinder bores which were fine. The salt air and temp in FL will degrade the rubber and upholstery. If the car was garaged the upholstery is ok but old age and salt air eats the rubber seals---probably the cause of your leaks. I do all my own mechanic/electrical work. If you do the same and stay away from the MB dealer$$$$$$, the car is not too expensive to own. On the web, autopartswharehouse for new parts, manuals unlimited for CD manual, Pull a Part or other pull yourself junk yard can save you a ton of money. Being fairly pedestian (cheap) Monroe shocks seem to work just fine. Does owner have servive records? If you need help Email me. When I got mine I went thru the whole car, I could perhaps save you some time

Mine is still doing fine ... I would recommend you remove the intake manifold and the crossover pipe, clean them both of what is likely a huge amount of gunk, then remove or disable the EGR valve - personal opinion only, but I continue to believe there may be a connection between the failures of these engine and the amount of gunk that is created by appears to be a too closely located EGR and valve cover vent (where it allows oil fumes to enter the intake).

May be nothing, but the amount of gunk was incredible!

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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