Taking this car to a compatent mechanic for a pre-sale inspection is a MUST
and make sure he's throughly familar with MB Diesels especially the 3.5.
Cracked Heads, Bent Rods, Bad Timing chains are not uncommon for these engines. Buying and older Mercedes without a good service record is a BIG gamble.
Be carefull

You need to do a search regarding this vehicle and the engine.

Suffice it to say that all 3.5 litre turbodiesel engines from 1991-1995 have a design flaw in the connecting rods. For reasons unknown, they may bend one of their connecting rods. This occurs without any notice and without any catastrophic failure. The engine just begins to ovalize the cylinder and begin to consume more oil. By the time you realize that 1 quart every 1000 miles is just too much, you are looking at about $7K to fix the engine.

Unless the connecting rods were replaced in the vehicle that you are considering, you must understand that you are rolling the dice with this engine. Some forum members have the engine and it continues to run without a problem. Other members have suffered the connecting rod failure, and have faced a large expense.

The choice is yours.

Thanks, Brian. Last year I mentioned buying a 350 and Zeitgeist and others busted my chops for NOT knowing about that potentiality. After I staunched the bleeding wounds, I I did a search and read a lot of discussion about it. But I don't recall any diagnostic methods other than lube oil consumption (dino or synth? -- just kidding) and perhaps uncharacteristic noise. But since I don't know what 'normal' noise is and a seller can lie about oil consumption I didn't know what to do. Suggestions would be most deeply appreciated. But I will def ask about oil consumption and engine probs.

On the plus side, some owners on this forum seem quite happy with their 350.

What would you think would be a reasonable budget rehab/maintenance expectation over the course of the first year?

The sinister part about the 350 is exactly what you have stated. You cannot hear the problem and, short of removing the head, you cannot see the problem. It all comes down to oil consumption. As you are certainly aware, there is no way to ensure that the vehicle burns one quart every 4k miles, as it should, vs. one quart every 1k miles, which indicates that the engine is well on its way to a rebuild.

When the engine is running well, it is a very fine vehicle. I have always been tempted by this vehicle. I am just hesitant about rolling the dice.

I am somewhat concerned about the $7K price. A 1991 350SDL would normaly sell for at least $10K if it is in good condition. My first question would be why this vehicle is offered $3K below market. Just as a comparison, my SDL, a vehicle that is five years older, was priced at $7.2K. This is not an excessive price for a 1986 vehicle with 110K on the clock.

I have owned the SDL for eight months now. I have done quite a few things to it, including a complete brakes, tires, wheels, shocks, and misc. other items for a total approaching $3K. Depending on the condition of the '91, you may be looking at somewhat less cost than this. However, Hattie has spend about twice this amount on his SDL, which he also has owned for about eight months. It all depends on the maintenance that has been done to the vehicle over its life.

You have not mentioned the mileage of the 350SD. This, including the maintenance records, would determine the amount you will spend in the first year. It could be as little as $1K if you are not a perfectionist and the vehicle has been properly maintained.

edit:

To put a scare into you:

results of compression test, 1991 350 SD

Thanks Brian, I have been following that thread.

All it said in the classified ad was 1991 350SDL $6,700 and the usual fluff about style, prestige, etc. I'm waiting until about 10AM this morning to make the call to see the car. After that I'll have a lot more info.


Here's what I'm betting. The car is one-owner, immaculate, garaged and about 120K miles. The interior is pristine. But the owner has pampered the car since he bought it new. He recently noticed the severe oil consumption problem and was told about the $7K repair. He's decided to buy a new S-Class and sell this one. So I look at this nearly cherry car with a blown engine. Whadda I do? Perfect storm.

If it still looks interesting to me after I actually see it, I'll post my observations here and see what you (all) think. Nothing like a group of strongly opinionated experts to keep you straight. What a resource!

$7K is too much to pay if you need to replace the engine. You cannot pay more than $5k. I do not care if you can eat off the bottom of the oil pan. Do not pay more than $5K for it.

Then, you have the option of spending $8K for a new motor and you have a perfect vehicle for $13K. This is exactly what a pristine 1991 300SDL is worth. Might even be a bit more if it is a factory engine.

The other alternative, if you have the capability and the resources, is to install a good used 603.96 engine. Total cost will definitely be less than $4K even if you have someone else do it. Now you have a fine vehicle for $9K. The vehicle is probably worth about $11K with the alternate engine and you have a good deal.

Thanks, Brian.

200K miles.

I did only a cursory inspection. The guy keeps the car garaged and waxed and it's white and its been raining pretty hard. I'll drive it on Monday when weather is supposed to be a bit better and wifette is back in town.

The white paint is clean and lustrous. No chips or rust or scratches. It has one small door ding. The paint on the flashing (whatever you call it) between the front bumper and the body has some discoloration or differential mottled fading. One headlamp enclosure has a star. I opened and closed two doors and they opened easily and shut soundly. After market dark window tinting is beginning to show age.

Owner claims all electronics and mechanicals work except the sunroof, which he says activates but fails, throwing a breaker. Breaker? I thought it was fused.

Driver's seat has a patch where you'd expect it: low on the driver's side seatback by the door where the seatbelt rubs. Aside from that the upholstery is smooth, pliable, wrinkled but not broken of worn. The carpets are worn but not torn or badly discolored. The paneling looks almost new. Looks like somebody pulled the dashboard and didn't reinstall it properly as there's a 2-3 mm gap between the lower shelf and the main dash assembly on the left side. Looks like some velcro is not attached in there. Dunno what that's about. Hope it doesn't squeak. I hate squeaks in the dash.

Owner claims complete repair receipts. Haven't seen them.

Yokahama tires are fairly new, 5K miles I think he said.

Previous owner was a pilot in Dallas who also has a grey SDL. Anybody know him?

The engine compartment is immaculate. Owner had warmed engine before I came. I saw no leaks, though he said there was some weeping near the injector pump. He says the car gets about 27 MPG on the highway.

Owner is a diesel mechanic who buys, works on and sells used 18 wheeler tractor rigs on eBay. This is his first Mercedes. He thinks he wants a later model gasser from what he's read so I'll go back in my 95 E320 and let him drive it to give him an idea about gassers.

I get the feeling from looking at his shop and stuff that he's a pretty careful, demanding kind of mechanic. Its neat but not perfectly so. Clean, too. Several DYI projects successfully completed and integrated into the shop, built atatched to his home. Also, he seemd like a stand-up guy. This is a confidence builder.

On my next visit (Monday) I'll drive it, look at his repair records and get the VIN.

Bot

I consider it a disfavor to have the car warmed up before I arrive for a test drive. I want to see how it starts when the engine's cold.

How's the ACC? Should function like the system in your 95 E320.

Sixto
95 S420
87 300SDL

Botnst it sounds like a good example pilot's tend to take care of their cars. 200k miles is good most 350's that fail seem to die young. If the records check out and it runs and drives good $7k is a good price. But make sure before you buy it you are ok with the fact that the engine could die one day to the tune of $7k.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Bot, I know it all sounds good and it may be a good deal for you. I'd negotiate, see if he can come down off that price. That engine is probably fine and but the chances of those rods bending increase each and every day. You may drive it one week and all goes bad, you may drive it 5 years and nothing. If you want it that bad go for it, but most likely you'll be out $7k on top of your purchase and maintenance. To risky either go for a '86 300 SDL or an SD with the 617 engine

Risky >

It depends on your risk level and how much money you can afford to spend. Frankly I think a 1995 300SD (W140 I know )would be a great car and would own one if I could afford to drop $7k if or when the engine dies. The 350 is a great engine more power is a nice thing to have in a heavy W126.

I wonder how hard it would be to find a 350SD/L with a dead engine and then find a 98-99 E300D that was smashed hard from the side or rear?

A W126 with a turbo 606 would be just about perfect.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I've been looking at diesels for about 1.5 years. I've looked at several early to mid-eighties turbos, a 240D but only a very few 126's. Of them all, I sure like the look and feel of the 126. It really does scream style, class and elegance. I have plenty of cars and can easily ignore this urge and live a happy, full life.

BUT! The car is pretty nice. If the records indicate that the rods have been replaced I don't think I'll be able to resist.

Sixto, I agree with you concerning starting the car. Its a used car lot trick and it works. But I'll take it out for a long ride and go on the interstate and take that sucker up to 90 for several miles or so and see how it rides and runs. The A/C is R-12 (somebody tell Larry Bible that I'd leaving R-12, cross my heart) and cools great. But heck, its mild temps here, so its hard to tell. The time to tell is in late July. Most cars have a hard time keeping up then and in my experience, the 1980's Mercedes were not designed for really hot, humid weather. Even my 95 E320 has a time of it.

Botnst,
Boy what I dilema, I share and feel your pain! I am looking at a 91 350SDL blue with 221k, ask is 10,500. local dirt/kinda asphalt dealer .

I wish money was no object...but it always is. I looked at a real, real nice one, with only 53k miles on it in California, but the guy wanted 19,000. but meanwhile he had invested over 30!!!!

I guess when we (I am including me and you in this thought ) think about it, what other kind of car could we buy for under 20,000. (purchase price plus new engine) that has the style, room, ride, and overall durability of a 350SDL?.... none comes to mind.

But I am practical, and to spend money on a depreciating asset, that is worth less the moment I buy it, is tough to swallow, to think I may have almost twice what it is worth...in it.

Wow, I think I just talked myself into the 19,000.00 SDL, and just save up for the new motor!!!!!!!

Verklemped!!

Joe

If the records indicate that the rods have been replaced, you definitely have to buy it because it will be a fine vehicle and you will have no risk.

But, if the rods have not been replaced, and you can somehow confirm the that the current level of oil consumption is less than 2 quarts every 5K, then you have a decision to make.

The risk is always present that one rod will go. If you are prepared for this risk, then 7K is about the right price for one of these with 200K on the clock. Then tend to sell for 10K or a bit more when the mileage is closer to 100K.

Now, with regard to your previous question concerning how much you will need to put into it in the first year. A vehicle with 200K, unless maintained very scrupulously, will definitely need $2K-$3K of miscellaneous odds and ends, including cosmetic BS in the first year. See if you can pull one of the front wheels and take a look at the front end components. If they are all original, you are now looking at some serious parts costs in the first year.
Hopefully, with 200K, some of the joints have been replaced.

If you really have your heart set on one of these, I would recommend that you look for one with lower mileage on the clock, with the rods replaced somewhere in its life. They are not around every day, but, there will be very little premium on such a vehicle, because not everybody understands what we all understand. You will pay $11K for such a vehicle, however, it will be the better buy, IMHO.

Brian is right, But if the $$ are a question then you'd be better off buying this one, but heck if you can afford more and want a better, low milege car do that.