Because of my current financial situation (not great) I got rid of my car (non MB) and am now looking to buy a second 300 diesel. At this point, I am focusing in on an SD to join the Stable.

I have not been successful in finding out the cosmetic, feature and mechanical differences between the various years, so I ask my fellow MB friends what if anything is different between the 81,82,83,84 and 85.

Thank you
Don

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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it

Well, while Thomas made a good summary on the "do's and don'ts" I'm just going to add that while looking into a 300SD, you may want to look into the 300SDL Turbo (Tom did mention the warping heads) Keep in mind the 617 5-pot needs valve adjustments every 10-15k. When you are as well versed as Thomas (and he know's his stuff) valve adjustments are a DIY job, but for the laymen owner, it's a few hundred at a good shop. The OM603 block as found in the 300SDL is quieter, faster and cheaper to run (if you don't overheat it, causing the head to warp and crack.) Just a minor addition, thought it was worth pitching.

All 300SD years are solid, the car didn't really change too much over the span of 5 years it was offered. Just be wary of rust (the panels of the SDs are very thin, some even aluminum) and abusive past owners.

I'm a new '84 model owner (77k miles) and really like it. I did swap out the intake/exhaust manifold with one from a '79 to simplify some stuff. It is a really nice, good running car.

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Jim

This being 20 years later, condition will probably be the determining factor in buying a car. Buy the best one you can find in your price range. But you probably don't want to hear that.

1985 had a single year specific turbo and transmission, which would make those parts harder to find. Also figure in the trap oxider mess, and 1985 seems to be a year to avoid. I don't think the 81 to 84 cars had any glaring faults.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

All 5 cyl 300SD years are pretty solid, but as a Californian I would avoid the 1985 which came with a trap oxidizer (emission device), renowned for shedding particles and destroying the turbo. MB had a free replacement program to replace these (after they got tired of constantly replacing turbos) with a truly passive device but I would suggest checking with your dealer before buying a 1985 to see if they will still honor that.

The general rule many follow is to buy the last year made in any model line, by which time the kinks have been worked out, but this does seem to vary from model to model. Reading this forum, the W140 chassis seems to have been exceptionally problematical in its early years (1992/3) reflecting its great complexity whereas the W126 (300SD, etc) seems to have been pretty solid most years, with the caution that you should be very careful with any six cylinder diesel which is likely to crack its head (300) or destroy its con rods (350). By contrast, the 5 cyl 617 is as solid as they come. In case you breach the faith and go with a gas engine, know that early pre-1985 380 gas engines have a single row chain that breaks if not monitored.

The 1984 had improved transmission control compared to the earlier years, so maybe that's the best year to get. Check for broken driver's seat springs - the gussetting was poorly designed/welded on early W126 chassis causing the seat to lean to one side and hurt your sciatic nerve. Easily rewelded or replaced with the differently gusseted redesigned spring - ask me how I know! Overall, the 5 cyl 300SD seems to have been remarkably free from year-to-year changes during its 1981-1985 life. Maybe others could chip in here?

Things like ABS, driver's airbag, rear headrests, factory alarm, power front headrests, memory seats and central locking actuation from passenger side and trunk were added as stadard equipment or options over time. Maybe orthopedic seats as well.

I prioritize condition and color combo over a particular year, myself. I'm turned off by the added complexity of an 85, but I wouldn't dismiss it. If you're used to cars with all around central locking, you might lock the trunk and leave unattended your unlocked early SD.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Just add remote locking.

ABS is nice, but the bags are only warranteed for 10 years, extended to 15 recently and replacement bags are wildly expensive.

Wonder which year the emergency seat belt tensioning retractors came in? My 1990 560SEL has them, the 1983 300SD does not. No air bags, ABS or memory seats on the latter either.

Also, am I right in thinking that no 5 cyl diesel W126 had the tilt roof and that all had the sliding roof only?

My '84 does not have ABS, air bags nor the tilt sunroof.

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Jim

I think the tilt roof is an 86-up thing.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Was the rear axle gearing differently in 1985 to confer lower cruising revs?

Also, did the last year(s) come with rear head rests? (Mine does not have them).

I'm guessing reclining/heated rear seats came later - anyone know?

Just curious, now that we are into this topic.

If you are interested in a later car, check with 'gsxr' on this board (Dave Meimann) - he's really expert on the 6 cyl diesels and can tell you how to identify a 350 which has had a factory replacement by its serial number. Now THAT would be the diesel to own. All the luxury and accoutrements of a 560SEL with none of the fuel consumption. Plus 'engine replaced' is likely to put most buyers off when, in fact, it could be the ideal car.

Needless to say, that magnificent Manganese Brown color was discontinued after 1983, so you may have to get a pre-1984

....brown.

Reclining and heated rear seats were standard equipment on 500SELs and 560SELs, optional separately on other LWB models... in the US.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Because I wanted a car sooner rather than later, today I purchased a 1983SD with 242K miles. The exterior was repainted and all the brightwork is really good. It has been in CA. all its life and no rust of any kind. Overall I give the exterior a 8.5.

The trans feels fine, but because of vacuume and linkage issues it doesn't shift properly. The engine is only getting about 40% throttle as the pedal only has maybe 1 1/2" movement between idle and full throttle. Oil pressure was good, no blowby that I could see, idled smooth. Temp seems a bit high to me, cruise is out and while the air works, it doesn't direct it properly.

The interior is a mess. Need new spring bottoms, cover for the driver seat bottom, need to reattach the wood on the dash, replace the wood on the shifter fix the tach and clean, clean clean and then clean somemore. Power seats partially work, door locks non-functional.

The suspension and brakes have issues, no idea what as yet.

So overall I would say that the mechanical condition and structure and the exterior are great and the suspension, brakes and interior stink.

They were asking $2,900, bought it for $1800.00.

Now if I can only find time to work on it as I have a few projects going on the 300TDT.

Thanks for all the input

Don

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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it

I have an 83 also, and I purchased it for the same price. It is a solid car and well worth the money. It is my first diesel and I love it. Mine has 319,000 miles on it and was rebuilt 60,000 miles ago. The interior is MBTEX and it is superb. The throttle linkage and bowden cable were way off when I got mine. If you know anything about these cars they are super easy to work on. If you need assistance just e-mail me.

Jim

Congrats.

I'm just down the coast from you in Santa Monica. I sent you a PM about getting together sometime to compare war stories. I've got a 300SD also.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)