Let's discuss W140 300SD cars

[JHZR2]

Yeah, the W140. Never thought Id say it, but I have a lead on one. Its a good deal (yeah, I know, nothing more expensive than a cheap Mercedes).

My w126 is very clean but Ive not been able to get the head gasket job done at my indy. He has run into issues twice and has had limited bandwidth since COVID. That's not really the discussion here though. This w140 car has a very clean (replacement) engine that runs well and strong.

My thought is that even if the w140 falls apart around the engine, it may be a good idea to have another OM603 3.5L engine if this one is really sound (will look at it a little closer very soon).

I know some things dont work - like the door closing assist. Not sure about AC (Its frigid recently). Interior is VERY clean besides the driver seat cushion. Car looks straight and decent. Clear isnt in the best shape, but that's not unexpected, IMO for a 20yo car that has decent miles on it.

My thought is that the car is either:

1) Useable as a stopgap until my w126 is fixed, then I either keep or sell it
2) Strong engine that I take as a donor for my w126 with whatever changes are necessary to convert the 140 model to the 126 variant (oil pan, mounts, etc.)
3) A complete flop at which point Id suspect I could still get $600 for the head, and some other money for some other key parts, and break even.

So, talk me in or out of it. I love older Mercedes, I love diesels. I dont really need another project, but this kind of intrigued me. For the money it seems maybe worth a try. Ive read the mixed reviews on the 140 cars. Some say theyre reasonable to keep up, others say there's nothing worse. But as a collector, trying one out for a bit isnt going to get any easier/better on this era of cars, and the newer ones dont necessarily interest me as much...

So, experiences with w140 cars? Pros/cons? Thoughts?

Thanks!

[87tdwagen]

You understand the constraints, you have a reasonable back up plan. If your cost can be easily recouped in pleasure and or in money, why not?

You already own a Panther, who wouldn't want a Tiger parked next to it?

[wallbenz]

Originally Posted by JHZR2

Yeah, the W140. Never thought Id say it, but I have a lead on one. Its a good deal (yeah, I know, nothing more expensive than a cheap Mercedes).

My w126 is very clean but Ive not been able to get the head gasket job done at my indy. He has run into issues twice and has had limited bandwidth since COVID. That's not really the discussion here though. This w140 car has a very clean (replacement) engine that runs well and strong.

My thought is that even if the w140 falls apart around the engine, it may be a good idea to have another OM603 3.5L engine if this one is really sound (will look at it a little closer very soon).

I know some things dont work - like the door closing assist. Not sure about AC (Its frigid recently). Interior is VERY clean besides the driver seat cushion. Car looks straight and decent. Clear isnt in the best shape, but that's not unexpected, IMO for a 20yo car that has decent miles on it.

My thought is that the car is either:

1) Useable as a stopgap until my w126 is fixed, then I either keep or sell it
2) Strong engine that I take as a donor for my w126 with whatever changes are necessary to convert the 140 model to the 126 variant (oil pan, mounts, etc.)
3) A complete flop at which point Id suspect I could still get $600 for the head, and some other money for some other key parts, and break even.

So, talk me in or out of it. I love older Mercedes, I love diesels. I dont really need another project, but this kind of intrigued me. For the money it seems maybe worth a try. Ive read the mixed reviews on the 140 cars. Some say theyre reasonable to keep up, others say there's nothing worse. But as a collector, trying one out for a bit isnt going to get any easier/better on this era of cars, and the newer ones dont necessarily interest me as much...

So, experiences with w140 cars? Pros/cons? Thoughts?

Thanks!

fyi- I have a backup 603 3.5... bought it for my 87 sdl- has #22 head...
I heard it run out of car... was very smooth. Don't know if it has updated rods.

Let me know if u r interested.

I have similar issues... keep? sell as is?? install in something else??

Just stinking up the back of my SUV now

[WDBCB20]

Originally Posted by JHZR2

This w140 car has a very clean (replacement) engine that runs well and strong.
it may be a good idea to have another OM603 3.5L engine if this one is really sound (will look at it a little closer very soon).

The above quote from your post is the strongest argument (in a weak field) in favour provide we're talking with documented certainty about one of those so called "Tauschagregat" engines that Mercedes shipped from the factory with the upgraded connecting rods etc.

[JHZR2]

Originally Posted by wallbenz

fyi- I have a backup 603 3.5... bought it for my 87 sdl- has #22 head...
I heard it run out of car... was very smooth. Don't know if it has updated rods.

Let me know if u r interested.

I have similar issues... keep? sell as is?? install in something else??

Just stinking up the back of my SUV now

PM or email me with what you want for it please!

[CSchmidt]

I had a 93 300SD and loved a lot about it. Ultimately its flaws caused me to sell it.

I didn't see what year the car you are looking at is. If in the "early" years there are a couple of things to be aware of:

- you know about the "rod bender". I bought mine with fairly low miles and no oil consumption. In 60K of driving it went to a quart every 400 miles while still running great.

- this is the bad wiring era. The biodegradable wiring harness insulation falls off the wires and causes shorts. A couple of time a month I would turn the key and only the SRS light would come on. I left a remote starter ( the switch with a wire that jumps the starter relay) installed. Leave the key on, hit the remote starter, a bunch of lights came on for 2-3 seconds, and then all was well again. Obviously it needed a new harness or two.

- Then the dreaded AC leak hit me on top of these 2 issues. Pulling the dash and replacing the needed parts is an epic task.

The combination of these 3 items led me to move on. I kind of wish I hadn't. It was a great riding car, mostly wonderful materials, and built like a tank. Good luck in your search

Chuck

[JHZR2]

Originally Posted by CSchmidt

I had a 93 300SD and loved a lot about it. Ultimately its flaws caused me to sell it.

I didn't see what year the car you are looking at is. If in the "early" years there are a couple of things to be aware of:

- you know about the "rod bender". I bought mine with fairly low miles and no oil consumption. In 60K of driving it went to a quart every 400 miles while still running great.

- this is the bad wiring era. The biodegradable wiring harness insulation falls off the wires and causes shorts. A couple of time a month I would turn the key and only the SRS light would come on. I left a remote starter ( the switch with a wire that jumps the starter relay) installed. Leave the key on, hit the remote starter, a bunch of lights came on for 2-3 seconds, and then all was well again. Obviously it needed a new harness or two.

- Then the dreaded AC leak hit me on top of these 2 issues. Pulling the dash and replacing the needed parts is an epic task.

The combination of these 3 items led me to move on. I kind of wish I hadn't. It was a great riding car, mostly wonderful materials, and built like a tank. Good luck in your search

Chuck

Yeah I’m looking at a 93 which isn’t the best, but far from the worst old MB diesel that I’ve seen. I know the harness and AC issues, amongst the other things that are often discussed. I’m primarily buying it because I am aware of the rod bender status, and I may want the engine for my clean w126 - the engine in this car is clean, dry, and shows no blowby. It is a higher mileage engine which to me implies it’s one of the engines that didn’t have the rod bending issue. I don’t see a factory replacement tag on the engine (I see one on the AT), but I wasn’t able to look that close/hard.

Of course to convert it to a w126 form would take some work but it’s things I’d likely do anyway….

So my take is play with the car a bit, get my w126 “keeper” back to functional status, and as that happens, either donate the engine from the 140, or sell the 140 with just a few miles on it.

[JHZR2]

Originally Posted by WDBCB20

The above quote from your post is the strongest argument (in a weak field) in favour provide we're talking with documented certainty about one of those so called "Tauschagregat" engines that Mercedes shipped from the factory with the upgraded connecting rods etc.

Definitely found the little metal plaque on the AT; didn’t see one or look hard enough on the engine… will do so.

All the same the engine started rapidly in 19F weather, fully cold soaked, after sitting a while and smoothed very quickly, showed no blowby, and is only an insurance policy anyway…

[fonzi]

What I read here is that you are reliant on a mechanic to do some work on your w126 that I assume you know very well by now. Yes, a head gasket replacement isn’t a tiny job, but it’s a sign that major engine work isn’t something you do, perhaps for space, or perhaps for time. Do you have the space for the extra car? Another project? These things pile up fast, and unless the car is really nice, it’s an effort to get rid of cars. Personally, I’m not sure I can find time to scrap one and pack away the parts in less than 3 months each. If selling parts off it at the same time, I think 6 months is more reasonable, and at that point I hate every car at the end. Sure, each brings some extra packet change, but I definitely haven’t had many requests for parts from the salvage title, running, driving 1993 300se I bought for $300. Thank goodness someone bought the wheels for $300. So anything that’s left is gravy, I guess even the catalytic converter for the guy that stole it.

These are big cars, and they, like an R129 ride and handle like a dream, but have wiring issues throughout.

If you need 1993 parts, I know where a car is located. Like you, I bought mine for the motor for potential swap projects, but have not found anything perfect to put the m104 motor into yet. It feels like 10 years later now.

[JHZR2]

Originally Posted by fonzi

What I read here is that you are reliant on a mechanic to do some work on your w126 that I assume you know very well by now. Yes, a head gasket replacement isn’t a tiny job, but it’s a sign that major engine work isn’t something you do, perhaps for space, or perhaps for time. Do you have the space for the extra car? Another project? These things pile up fast, and unless the car is really nice, it’s an effort to get rid of cars. Personally, I’m not sure I can find time to scrap one and pack away the parts in less than 3 months each. If selling parts off it at the same time, I think 6 months is more reasonable, and at that point I hate every car at the end. Sure, each brings some extra packet change, but I definitely haven’t had many requests for parts from the salvage title, running, driving 1993 300se I bought for $300. Thank goodness someone bought the wheels for $300. So anything that’s left is gravy, I guess even the catalytic converter for the guy that stole it.

These are big cars, and they, like an R129 ride and handle like a dream, but have wiring issues throughout.

If you need 1993 parts, I know where a car is located. Like you, I bought mine for the motor for potential swap projects, but have not found anything perfect to put the m104 motor into yet. It feels like 10 years later now.

I have plenty of space and garages. I dont have time because I have small children that I want to spend time with. To a great extent we all enjoy driving around in the different cars, and my wife tolerates it/me.

So no, I dont have 20+ hours to devote when I have other demands. I dont mind paying a shop for a job like that, as much as Id be generally interested in doing it myself.

A 6 month project is a good angle, may keep it a bit longer if the engine proves out to be really good... Or I can sell it for what I bought it for. The diesels are more rare than the ga$$ers, less the V12 models I guess...

If nothing else it scratches an itch for a while and Ill get something back. I think really Id like a W124, maybe a 201, and/or a 107/129. Lots of "wants". I may just cycle through cars a while to see what I really want/like.

But I know the 603 and servicing the mechanical/suspension parts well enough that knock on wood I can keep this one running a while...