Hello my fellow Benz owners. As usal this site has always been a source for myself and my 5 Mercedes over the years. I usually only do a lot of reading here, it's quite enjoyable. Recently when getting some information of fixing my Closing assist pump on my W140, I stumbled across some articles about certain diesels being "rod benders". Of course, being a diesel owner this concerned me, so I started reading more into it trying to gather as much information as I could before I make any decisions. My favorite car that I own is my 1994 S350 Turbo-diesel. It is of course a W140 model chassis and has been the best car I have ever owned. I am the second owner of this car and I have had it for a number of years now. It has been perfectly maintained as well as any DIY'er can do not to mention as many trips to the mechanic, nothing out of the ordinary. When I bought the car, I now remember the first owner (who was a minority owner in the Baltimore Orioles) told me this car had a recall on something to do with an oil leak so instead of getting the leak fixed like everyone else, he made them change the whole engine out. So he mentioned to me the engine acutally only had 75,000 miles on it as opposed to the 100k or so on the speedometer. Well the engine looks as great as the day it was put in, it stills has the yellow velum, used for shipping purposes I believe,on most of it. I keep it VERY clean. Now that you guys have a little background on the car, which in now at 170k, I hope you cna help me with this issue. I am not even sure if any background helps or not but why not right?

1. How can I tell if this car falls under the "rod bender" category?
2. On the head of the engine it still has a sticker that reads 603-971 so I am assuming this is the engine model and is this one of them?
3. I read in a post one of the engines to look out for is the 603-970, are they the same and what are the differences?
4. Would it be safe to assume that when the engine was replaced, if that information was true, would that have fixed any potential problem by that time?
5. Could it be possible that the "oil leak" the old owner told me about was the "rod bender" problem and either I misunderstood him or he was just being evasive using the "new engine" as a selling point?
6. Am I even worried about nothing and this car was never in the "rod bender" category?
7. Any other questions I should be asking or one might feel to throw into his/her response?
8. If this engine is doomed, short of selling the car, what can I do? I have read to replace the old rods with new rods. How big of a venture will this be? Is it a shop thing or something a pretty good DIY'er can do under the hood himself? Is this an expensive process?

Thanks a million guys for any responses. I now can'tget it off of my mind since I read about this problem. My wife and I are going through some hard times right now and can't afford to have something drastic like this happen to us right now. Any information is greatly appreciated!!!

 

I will put my 2 cents in for you.

The 350 diesels are notorious for being rod benders. What does that mean. From what my mechanic told me, the 300SD's and 300SDLs being 3.0 liter cars do not have that problem. When Mercedes made the 3.5 liter engine (S350, 350SD and 350SDL), it was not correctly designed and the rods can bend in the engine.

Now the problem. Unfortunately, you can drive a 350 Diesel forever and have no problem, but you can drive one that was PERFECTLY maintained and the engine goes. There is no real way to tell. Anyone who tells you that either doesn't know what they are talking about, or is not telling the truth. When the 91 350's came out, some of their engines died and people made a real stink with Daimler. They bought brand new cars and they died within a couple of years. As I understand it, Mercedes "quietly" replaced a number of engines for people who were making a big stink.

I, too, like the 350SD and SDL and even the big body S350, but you run the risk of the car dying because of this at any time. Like I said, it may never happen, but you dont know with that 3.5 liter. I have heard of some going to 200,000+ miles with no problem, and others dying at 100,000 or 150,000. No real way to know.

So, my recommendation, drive it carefully, enjoy it and if it happens, there is nothing that can really be done.

In my opinion, the best S Class diesel with the 84 and 85 300SD. I had one in mint condition with 80,000 miles and never planned on selling it, but one day at the gas station I was fueling her up, and an older gentlemen pulled up with his diesel (300D) and love the car and made me an offer on the spot I could not refuse, so I had to part with my baby Anyway, I am presently in the market for a mint condition 86 or 87 300SDL.

Anyway, sorry for the long post, but I thought I would put my 2 cents.

 

neighbor s father across the street, has s350, 120 k or so on odo, owned since new, bad on maintenace, still goes, no odd noises out of original engine.

i d tend to agree with last post , a hit / miss on the 350.