300D question... what year is best? - PeachParts Mercedes-Benz Forum

geekcomputing · #1 04-23-2006, 04:04 AM

I'm looking to get a 300D or a 300Sd

My question is

of the years 1980 through 1985 what is the best year and what is the worst?

what are the differences between the models?

thanks,
mercedes noobie.

jfman · #2 04-23-2006, 04:10 AM

Dont take my word for it but I was told 85 is the best for fuel economy cuz it has a taller 4th gear. The earlier ones do not have turbo and they are slower. I think '83 is when they came out with the turbos.

BTW: I'm a MB newB too, someone with more extensive knowledge will chime in I'm sure.

t walgamuth · #3 04-23-2006, 04:24 AM

well they introduced the turbo in 79, i think, in the sd.

and the early non tubo 300s were pretty economical too. i would be surprised if the turbos out did them for economy under equal conditions. the non turbo engines have the advantage of simplicity with one less system (the turbo) to maintain. and engines with out the turbo would go longer without changing the head gasket too for example. and the other parts under the hood prob will last a bit longer too like rubber and plastic parts because of less heat in that area.

so yeah, i have heard that the 85s are the best, but for cars this old, any of the years you list are good solid dependable autos if in good repair. i would recommend buying the nicest one you can afford regardless of the year or model. the newer ones will have more power gadgets to go wrong and maintain but the same potential maintenance headaches are that which offers you extra features, so you just have to choose and go for it.

the newer years are better for rust too, so if you are in the rust belt that is a consieration.

i recommend a good checkup including compression testing to be done by a mb diesel experienced mechanic before purchasing.

tom w

MBeige · #4 04-23-2006, 04:46 AM

For some reason I rarely see an 82, mostly an 83 or 84, second rarest the 85 out of the turbocharged models.

The W123 1982, 83 and 84 are pretty much similar. Interior trim is where the 85 and 84 differ from the 83 and 82. The 85 has the taller 4th gear and also I've heard the valve body is more durable on those transmissions. The 85 also has the Kilma relay which amplifies vacuum levels to provide more vacuum (like a storage area). Some really late models have an overboost protection device that's run via vacuum and goes to the kilma relay for any additional vacuum.

Some models have the trap oxidizer which can be a problem (84 Cali version?). Other models also have a different air intake and exhaust downpipe that's higher in the engine bay and hence forces the air filter to be relocated forward behind the passenger headlight. A friend's 85 has this.

About the SD, if you're talking about the 1980 then that's a W116. If it's a 1981-1985, that's a W126.

jfman · #5 04-23-2006, 04:50 AM

Quote:

Originally Posted by MBeige

The W123 1982, 83 and 84 are pretty much similar.

About the SD, if you're talking about the 1980 then that's a W116.

If it's a 1981-1985, that's a W126.

I guess this is another newB question:

How can it be a w123 and a w126 at the same time. ?

t walgamuth · #6 04-23-2006, 05:21 AM

you are correct it is one or the other.

three body styles have been mentioned:
the 116 is the s class car ending in 80 or 81. it was replaced with the 126 s class in 81 or 82. the smaller car was called the 123. this ran from about 77 to 85.

in the diesels, there is a lot of similarity in all three cars. the s classes were never offered with the na diesel at least in this country.

if you are looking for simplicity, you might also consider the 240d which is simpler lighter and uses the four cylinder engine. also came with a stick or automatic. the others all came automatic only in the US.

the 240 is a lot slower but easier to maintain. if a stick it is engaging to drive, with an automatic it is pretty close to dangerous becasue of lack of acceleration.

good luck

tom w

rhodes2010 · #7 04-23-2006, 06:40 PM

My 1980 300D has the Auto Temp II climate control system.
Had I known what this meant I would have gone after a 1981 or
above.

And.... I really like my non-turbo 300D, but I think I would enjoy it more
with a turbo.

bud640 · #8 04-23-2006, 07:34 PM

Quote:

Originally Posted by jfman

Dont take my word for it but I was told 85 is the best for fuel economy cuz it has a taller 4th gear. The earlier ones do not have turbo and they are slower. I think '83 is when they came out with the turbos.

BTW: I'm a MB newB too, someone with more extensive knowledge will chime in I'm sure.

I have a 81 300TD. It is awesome.

TheDon · #9 04-23-2006, 07:40 PM

85's were the last year for the w123 and most of the bugs had been worked out

Austin85 · #10 04-23-2006, 07:54 PM

If you don't have a Turbo, drive around for a while with a few heavy people in the car;
And then when you drop them off , you feel like you have a turbo!!

JimmyL · #11 04-23-2006, 07:59 PM

I've had an '80 wagon, non turbo, and I currently have an '85 wagon. I've driven an '83 or '84 300D (I forget the year). The tranny in the '85 shifts like a completely different car than the previous years. It's a one year wonder, but it is simply a much better shifting tranny.
Having said that, the difference isn't near enough to make you want to find an '85 only. The other years are fine, and as stated, condition and history are the big items of value.
I had no problems with my '80 as far as it not having a turbo. Would still cruise down the freeway just fine, and the engine doesn't seem to get quite as warm.

Also, as kinda stated above, the SD encompassed two different chasis styles.
78-80 was a 116 chasis, VERY prone to rust. (I've never seen one without it) Then the 81-85 was the 126 chasis. Also, the 86-87 126 chasis was the SDL. Same chasis basically, much different motor.
300D's, 300CD's, 300TD's, and 240D's were all 123 chasis from '77-85.
Find a clean one, and good luck.
Don't find a clean one and it becomes a hobby and part time job......

#12 04-23-2006, 08:16 PM

This thread has gotten a little confused, maybe I can help a little.

The 300D is a "midsize" (like the current E-series), and it's a W123. They were made with a non-turbo engine from 77 through 81, and a turbo engine from 82 through 85. The exception is the W123 wagon (300TD) which got a turbo in 81. The 77 through 81 (non-turbo) cars are very similar, and the 82 through 84 (turbo) cars are very similar. The 85 has a few changes that make it unique. It has a higher final gear ratio that improves mileage. It also has a somewhat different automatic transmission design. There are a few other details in the electronics that are different. The 85 300D cars that were sold in California also had quite a bit of additional pollution control equipment, and those cars are usually not considered desirable. The 85 California cars can be recognized by their large "canister" type air filters. As for the "best" and "worst", condition is more important than model year. If you want a turbo, you are limited to 82 to 85. The 82 through 84 models are essentially identical. The biggest advantage of the 85 is the higher gear ratio, the biggest disadvantage is probably that there are less used parts available for the unique pieces. My advice is to look at the condition and maintenance history, don't worry about the year.

The 300SD is a "full-size" (like the current S-series). The "old" style 300SD is a W116, made from 78 through 80. The "new" style is a W126, made from 81 through 91 in various versions. From 78 through 85 the 300SD used the same 5 cylinder (617 turbo) engine as the 300D. After 86 it used variations of the 6 cylinder (603) engine. I'm not an expert on the W126 300SD, but I don't believe there is not not much difference between the 81 through 85 models. Again, I would pay more attention to condition and maintenance history than model year.

t walgamuth · #13 04-23-2006, 10:48 PM

one minor thing,

i seem to remember that the cd might have gotten the turbo one year earlier too.

tom w

#14 04-23-2006, 10:52 PM

Quote:

Originally Posted by t walgamuth

one minor thing,

i seem to remember that the cd might have gotten the turbo one year earlier too.

tom w

I didn't think so, but I may be wrong.

t walgamuth · #15 04-23-2006, 11:04 PM

me too. this is a vague memory from reading road tests back when they were new.... and it could have been some other feature that was offered earlier on the coupe.

tom w