some questions about 80's diesel mercedes

texcl

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I'm looking for another sedan that gets 30 mpg's + and is a simple diesel. I've owned several VW's and have 2 complains, 1st there is no room to work on the TDI's especially the beetles and second they have a horrible electrical system. will the mercedes meet my MPG requirement? which models were more economical? the VW had horrible auto trannys how about these? Are parts expensive? Any models to look for or steer away from? Thanks for any input.
 

Shadetreemechanic

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Auto's on the benzes are good, but it will be hard to break 30 consistently in a 123 unless its a 240.
The 123's definitely have the cheapest parts. From your description I would say aim for an 80s vintage 240. I would only want a 240 with a manual transmission because of the low power, but there are a lot of automatics out there.
 

The Warden

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Agreed that 30+ MPG isn't realistic on a W123 chassis...I was able to get to 30 a couple of times with my old '85 300D (had a 2.88 gear ratio; earlier turbo cars had 3.07 axles), but 25 MPG is going to be more attainable on a regular basis.

I drove a 240D automatic for a couple of months, and was underwhelmed by its fuel economy...if anything, it was slightly worse than the turbo 300D's I've owned (I think this is due to the deeper axle gear ratio; 3.69 gears and the engine's really wound out on the highway). I only checked a few times, but IIRC it was in the 22 to 23 mpg range. A manual 240D might be better; another option would be to take a 300D turbo and convert it to a manual transmission. Keep in mind that, while the automatics are pretty good unless you abuse them, the top gear is still 1:1 and there is no converter lockout.

Another thought, if you're looking strictly for fuel economy, would be to get a W126 300SD, then find a gas 126 with a 2.47 rear axle. You'll lose bottom end power, but for freeway cruising, you'll do much better in terms of efficiency. A few people have done this swap; take a look around for some threads talking about the experience and results.

As to parts...there are a few good resources. I would recommend against getting a W116 car; parts for that chassis are considerably more expensive than for the W123/126 cars, and the climate control system is much more problematic (early 123's have the same problem).

Hope this helps some...best of luck ;Sweet
 

texcl

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Yup, it does. I am actively looking for a 240d now. Found some real nice candidates on CL but hard to get many of these guys to respond. There is a real nice 79 300d locally with 140k, no rust and runs well but has an a/t and he won't go below $2200. Plus it is that mercedes mucus yellow, my least favorite color.
 

The Warden

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Yup, it does. I am actively looking for a 240d now. Found some real nice candidates on CL but hard to get many of these guys to respond. There is a real nice 79 300d locally with 140k, no rust and runs well but has an a/t and he won't go below $2200. Plus it is that mercedes mucus yellow, my least favorite color.
FWIW you won't find a U.S. market 300D with a manual transmission. They only sold automatic 300D's in the U.S. There are some gray-market (built for and sold in Europe, then imported post-sale to the U.S.) naturally aspirated 300D's with 4 speed manuals (and a VERY few '84 and '85 with 5 speed manuals), but they're very rare and command a high premium.

This is just my opinion, but I wouldn't waste my time with naturally aspirated (pre-1981) 300D's for a couple of reasons.

First, it's not really practical to convert a n/a 300D to a turbo; there were a number of internal changes i.e. different valves, and simply slapping a turbo exhaust manifold on a n/a 300D is going to shorten the engine's lifespan.

Second, I mentioned in my earlier post that W116 chassis cars have a very problematic automatic climate control system; this also applies to pre-'81 W123's. The ACC on '81-'85 cars has issues, but is generally more reliable and less expensive to repair when something does go wrong. OTOH that's one big plus to the 240D; they have manual climate control systems.

Third, IMHO it's the worst of both worlds...you won't have the power of a turbo 300D (believe me, that turbo makes a big difference), and you have one extra cylinder to feed compared to the 240D.

If you're willing to have a project car, IMHO the ideal setup would be to get a 240D with a 4 speed manual and manual climate control, windows, etc. and swap in a turbo OM617 and rear axle out of a turbo 300D. That'll give you the lower freeway RPM's and better power (doubly so without the loss from the slushbox), along with the reliability and simplicity of a manual transmission and manual climate control. The later model ACC works nicely when it works, but is a major pain to diagnose when it doesn't work (being patient, having small hands, and being proficient with a MityVac will make life much easier)...and, I have yet to see an earlier model ACC setup that worked properly -cuss

BTW, I agree with you about that mucus yellow :puke: also, as much as I love the reliability of the W123 chassis, both of the 300D's that I owned have turned me off permanently to tan interiors...give me black or blue or gray or even bordello red LOL but I'm sick and tired of looking at tan interiors!!
 

txquigly

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Good morning! Been MIA for a while, but looming around again! As far as Benzes go, I've had a lot...got 5 now. I used to be completely SOLD on the old style OM617 engines....Indestructable, dependable and reasonable power. Don't worry, I haven't tossed them, just broadened my horizon a bit. I was recently in a search for the same 30mpg car for driving my daughter to school and back every day (100+ miles/day). Did all the forum jumping and research and ended up buying a 1995 E300D W124 body car. Had an earlier model several years ago with the 2.5 and while it was a good car, it wasn't the old 3.0 rock. This car has the OM606 DOHC 24V 3.0 N/A 135hp engine. Yes, I said natural aspirated...as in NO turbo. AND it's as zippy as the earlier 2.5 turbo I used to have! Plus it gets an HONEST 29-31 MPG!! I usually drive it like I stole it...75 to 80 on the hiways and foot on the floor in town (easy to do with no turbo) and I get 30mpg CONSISTANTLY!!! Now I've got a 1999 E300D W210...same engine with a turbo (175hp) and I haven't been able to get over 27 in it....can't keep my foot out of it! It's as different as going from an IDI to a powerstroke in character!!
I've done a ton more research on this mill and apparently it's the tuffest engine they've built yet. Europeans are getting well into the 400hp mark with stock long blocks and in the 700's with a modified engine!!! I'm looking for a pullout engine now to start experimenting with.
Gotta run...time to get ready for church!

TxQuigly
 

txquigly

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Go to YouTube and do a search for "mercedes diesel burnout" and "OM606" and follow the vids! The Euro drifting circuit winners are running these engines with huge turbos and kicking butt!! CAUTION ... these videos will make you cary a stupid grin around for a while!!!
 

Knuckledragger

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I'm intrigued. How do you identify the OM606? Does MB use it in the later (1999) turbo models?
 

txquigly

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1994-1999 ... after that I believe everything was "bluetec common rail". The OM606 is the only 6cyl DOHC diesel...injectors in between the cams in a hemi comfiguration. Beautiful engine really...
 

The Warden

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If I may ask, what did you pay for your W210?

If M-B had sold a 606-powered 210 wagon with a 5 speed manual, I might be driving that instead of my Jetta :angel: ...I've never had the chance to drive one, but have always been impressed with them ;Sweet
 
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