Would you be afraid of a 350 SDL?
 

A few have popped up for sale lately, I have always heard about the rod bending but not sure which ones, or the exact reasons leading up to it. I read somewhere that those that made it to 75K seem to be OK, but who knows where that came from? I only know one person who bought one, an independent Mercedes mechanic I knew. He left Tucson for Albuquerque with it and threw a rod before he got there.

I wouldn't be afraid of one because I wouldn't own one. Too many fiddly vacuum bits for the emissions controls, 350SDL specific driveshaft and engine mounts (which are very expensive), an ASD system that's a "meh" afterthought to adding traction control, and of course an engine that has weak connecting rods and an appetite for head gaskets. There are people out there that love them, but if you're not in the market for some potentially expensive repairs with hard-to-obtain parts, look for a 300SDL if you're wanting the LWB 126, or consider building a 3.0L 603 or 606 to go in there.

I loved mine...
 

I owned a 1991 350SDL. It was the smoothest and quietest running Mercedes I’ve ever owned. Yeah, I always had the rod bending fear in the back of my mind. A friend of mine wanted it more than I did and so I sold it to him. I don’t think there is a “safe” mileage to say that the rod bending doesn’t happen. It could happen at any mileage IMO.

I am half way through reading a very long thread on the 350. It is discouraging for the most part but then there are people popping in with high mileage and no issues. Too bad, there is a real low mileage beauty for sale here right now

https://tucson.craigslist.org/cto/d/1990-mercedes-benz-350-sdl/6406123948.html

Honestly no, I saw one in my city two days ago, I was driving right beside it.
They had the wrap around euro tail lights, it was a clean car too. Wish I had one.

Holy hell. I don't think even a Concours-ready model could get that kind of dough.

WOW! I should have held out selling my 350SDL a couple months ago. It was a very nice low mileage (120,000) example, I got $4,800 for it. I had all the service records since new, and no record of anything major like connecting rods. It was also white with grey interior......Rich

I wouldn't be afraid of it. If it made a 100k miles without bending a rod, it probably isn't going to anytime soon. I'd love the bigger turbo, beefier head and crank in my 87 300d.

The w126 300SDL with the updated interior, long wheel base is such a gorgeous car. Not a 8k gorgeous car. I don't think I'd pay anything more than 4k for any Benz between 1978 to 2004 since nice examples can be found cheap for any mercedes.

How different is 603.970 emissions from .96? .971 has vacuum boost control. Convert to pressure control when you lose boost.

Do most 350s out there have ASD? Most I see here don’t have it. But I agree it’s poorly designed because it’s dufficult to bypass when it stops working properly.

Sixto
98 E320s sedan and wagon

Nothing drives like 'em but between the connecting rod/hg issues and some parts being unobtainium, I walked away from 2 350SDLs (prior to buying my 91 300D).

I agree with Ben.

I had one for a while. it was not real high mileage, needed a valve job, had the intake clogged with semi hard black goo, and might have had the beginnings of a bent rod. It drove like a dream with bags of torque and reasonable economy, an excellent interior. I eventually sold it along to BC and bought a new Magnum.

I don't think there is a safe mileage to get past and I don't think MB ever truly solved the problem. they built it maybe six or eight years and eventually stopped building it.

I'd buy one if I could get a really clean one cheaply enough to put in a nice tight 3.0 liter motor and not be underwater.

I would probably roll the dice if I could get it for 1/2 that. Unlikely though, I Googled the phone number and it is a local dealer. They are asking NADA high retail. They will probably sell it to someone who doesn't know anything about the reputation.

They have that stupid vacuum wastegate for one, several of them seem to have the ridiculous ARV in the turbo outlet, different prechambers and injectors (which are actually a bonus in this case), I'm sure there's other things too. More vacuum gadgetry = more headaches.

It seems like a lot of the '91 350s have ASD. Not sure if they made it a standard feature right before they discontinued the car or what. '91 was a weird year with a bunch of 350SDL exclusive parts and options.

I have owned a 1990 350 SDL and had no problems relating to the engine. I do have issues with the monovalve which I replaced on the recommendation of a mechanic who was "clairvoyant" and knew that this was my problem (not).

At this time engine rod issues can be solved with the 3.0 liter lower or short block. Having to possibly deal with this at some point should be reflected in the cost of the car though. Really kind of a white elephant model in todays market.