What's the best year for the 300D?
 

Does anyone know which was the best year for the 300D and why? I tried several searches in the archives but couldn't really find anything.

Oh, and I'm sorry if this starts a debate =)

Alex

The best year is probably 1983. If I recall correctly, Mercedes Benz added some tighter emissions controls on the 1984 and 1985 models, more so on the 1985 because of the notorious trap oxidizer.

Keep in mind that the post-1983 models have better front and rear seat contouring, better front dome light, more rear knee-room, nicer door frame molding, (the felt one, that goes around the body of the car), velour weave carpet, and the 120mph speedometer. The seatbelts were easier to buckle too.

1982 models still had the "old" stuff. :(

I think we need limits, as the 300D was seen in both the W123 and W124 chassis. My '92 is a 300D, and has all the newer stuff that comes with owning a W124 (Airbags, seatbelt pretensioners, ABS, etc.). A 124 is more advanced for sure, but the 123 is bulletproof and relatively straightforward.

I vote W124, and likely for the 91-93 2.5 turbo or the earlier 86-ish 300D with the turbo 6-banger

85 300D 123 body
 

Is there a procedure to remove or disconnect the emission control devices that were added to the 85 300D? My friend, Alex, told me about disconnecting the vacuum hose from one of the units which circulates exhaust back through. Is there anything else I should do?
Also, I need to order the vacuum tubing that loops between the fuel injectors. What is it called?
Thank you. This is a terrific site!
ed

Drawde,

That little line that "loops" between injectors has something to do with fuel and is not a vacuum line. They do leak sometimes and should be replaced. Can buy from Fastlane....called looping braided fuel line I think. Very inexpensive. Just pull old ones off and push new sections on. No sealer used. Don't forget to put the plugged one on the last injector toward the firewall.

There is a contraption just to left top of engine as you face car. It sits right in front of air cleaner. Has a vacuum line going to it. That is an emission control unit that can be disconnected by simply removing the vacuum line and plugging up the ends. Apparently, some people put a steel BB into the line. In states where emission control checks are mandatory, be careful as they frown on this approach.

My car gets 1 to 2 miles per gallon better mileage with the unit disconnected.

Nic
'85 300CD @ 144k miles

emission control and fuel lines
 

Nik-
Thanks for the reply. Will order the hose from Fast Lane. Good idea about the beebee, thou I haven't seen one since I was 12.
Ed

best years for 123 diesels??
 

regarding the trap oxidizer..not on all cars...only put on the California versions...stay with the Federal version...they only have an EGR valve.

I will have to say that I am not very familiar with all the changes, but my understanding regarding the 84-85s is that they have an upgraded vacuum pump..piston type. In the older diaphram type, the diaphram could break allowing oil to travel via a vacuum line into the fuel injection pump...dirty oil in there would wreak havoc..if buying an older 123 you must check this.

I also understand that the 84-85's had improvements made in the tranny.

I have a 1980 300td.No turbo.Has less power than the turbo,But enough for me.Also it will last longer than the turbo ones.If I need more speed,I hop on my Moto Guzzi,our take out the 450sl.All the best michael.

Michael,

I sure agree that for most of us, the added power of a turbo is not essential. Mine is a turbo version but I have never been in a situation where a less powerful engine would not have sufficed.

I wanted to ask about your "longevity" comment. Before buying this car I always assumed that a turbo somehow stressed an engine and would, therefore, lead to shorter life. That just seems to be common sense.

But....I got ahold of an article in Car and Driver magazine from 1983 in which a turbo 300 was reviewed. That article said that the turbo actually improved the gas mileage of the engine. They gave a very technical argument that had to do with the way the combustion process occurs in a diesel vs. a gas engine.

I have also read many times that the turbo's life is similar to the engines and that it typically does not fail.

Being a bit paranoid, I'm wondering if you know something I don't about my turbo version. I sure want to think that the engine in my car is as durable as any other 617 diesel!

So my question is....does anyone have factual information regarding the relative life span of a turbo 617 vs. non-turbo 617?

Nic
85 300CD

NIC,

FWIW, I cruise the junkyards in Houston almost twice a month for the past six years or so. I have seen more normally aspirated (na) MB diesels in the yards than turbodiesels. Maybe three turbodiesels in all this time. I know this does not mean much, because I don't know why the cars are in the yard to begin with. Don't the na engines run at higher compression than the turbos, thus more stress at any given rpm? I know the turbo adds compression when its spooled up but its not running at high compression all the time. Plus, with oil cooled pistons, I'll bet my 617.952 will outlast michael rybikowsky's na 617 for sure ;) .

SW

sw.I wish you people would put your names.Every engine all things being equal have so many horsepower hours in them.The more power you pull out the shorter life.Not to mention having to replace the turbo that is turning a million rpm.Turbos are nothing but a stop gap messure to get more power,when the powers to be dont wish to spend the money to upgrade the power.

Michael R-

Since the only way a Diesel will produce more power is if you either increase displacement or increase both fuel & air getting to the cylinders, naturally a turbo's a better way to go...bumping displacement will kill mileage. Turbos simply compliment properly designed diesel engines...and since virtually no power's required to turn the turbo(s), it's a great solution. Far from an afterthought or stopgap measure.

And BTW, I think turbo impellers don't turn much more than 150,000 RPM:)

Bill and Michael (not michael r) you are absolutely right. Here are some statements from 1982 sales brochure that might be redundant to most of us but educational to those uneducated about the subject ;)

"The genius of the turbocharger is that it developes its extra power (45% more power than developed by the naturally aspirated version) almost literally from thin air. A turbine wheel positioned in the engines exhaust stream extracts energy that would otherwise be wasted and uses it to drive a compressor turbine in the intake tract-where its blades, revolving up to 100,000 rpm, pack the cylinders with an extra volume of air and so enrich the fuel air mixture that the increased combustion increases the horsepower. Without enlarging engine volume and without added mechanical upkeep; the turbocharger itself demands zero maitenance.

With added power come added engine stresses. In the turbodiesel version, more than half of this five-cylinder engine's internal components are enlarged, made more rugged, or otherwise modified. (One ingenius modification is oil cooled pistons. A steady stream of cooling oil is precisely sprayed into each moving piston from nozzles mounted in the base of the engine block.) The crankshaft is increased in hardness and doubled in fatigue strength by nitriding-diffusing nitrogen into its entire surface area.

The torque output of a turbodiesel engine is enhanced by 45%, lending vivid extra thrust :rolleyes: on initial takeoff and in mid-range acceleration. The higher rear axle ratio allowed by this extra thrust is what allows Mercedes Benz turbodiesels, for all their potency of performance, to hold the line on fuel efficiency. Horsepower radically higher, yet at the cost of not a drop more fuel consumed: had it not been so eloquently proven by Mercedes Benz turbodiesels over these past four years, it would almost defy belief."

It also says the turbo by itself only weighs 17 pounds. I wonder how many extra pounds of cast iron would have to be added to the block to get a 45% power increase? Keep those turbodiesels whistling.

If we could only actually hear it whistle over the Diesel clatter, but hey, I don't mind :D.

SV:

You can sure hear mine! That is, in the Volvo. Sounds like a police siren. So does the one in my brother's 87 300SDL. The 87 300DT is sort of a hum. My vote for best 300D is the 75 300D simply because is was the first! (only kidding, the 87 is the best, hands down if we are counting anything other than W123s! More power -- LOTS more power).

The Volvo turbo was re-sleeved with new bearings two years ago -- was quiet before that since it didn't spin very fast. My brother's was much quieter before he changed to Mobil 1 -- has a lot more power now, too.

Given that the turbo diesels are beefed up, I don't think there is much to chose from in terms of longevity -- even the horsepower developed by the turbo isn't exactly gigantic in comparison to that from similar displacement gasoline engines, and peak pressures in diesels are much, much lower than those in gasoline engines. If you get a good one and keep good oil in it, it shouldn't ever really wear out -- most of us won't actually put 500,000 miles on a car before the body goes.

Peter

The MB little D's are just as good as the big D's. A good diesel goes 400-500K before it needs any major work assuming it has been taken care of throughout its life. My uncle drives for WalMart and 500-800K miles is common on the big D's just for longhaul distribution. Leasing is push down the milage but all big D's have one some two turbo..... ummm a mercedes with twin turbos, now were're takin.

Seriously, I think everything else will get replace on the car before you do anything major to a MB diesel motor.

Morph

My vote for the best 300D is the 90-93 variety......airbags,better handling,smoother engine,better accelerations,quiter ,better mileage
I had one that I drove 208K and never put anything in it except glowplugs and regualtor


Warren
1992 300SD 124K
Columbus Ohio
turner@greif.com

What is best is what makes you the happiest.For me It is the non turbo.Best to all.Michael R.

The 85 IS King 123!
 

I do not agree on the 83 being the "best." While some may beg to disagree, I hold the 85 as the best year for the 123. Not only was it the last, but if you ask any mechanic, it has all the bugs worked out and has many improvements over the prior years. Among the improvements: vacume pump, fuel pump, cruise control configuration, and last but not least, the transmission modulation. There are a few minor touches, but if you ask any mechanic/Mercedes buff, they will contend the 1985 as best/final/most desired. (It is VERY hard to argue these points.)

are you saying you believe the 123 superior to the 124 of '87 and 90-93?????


Warren
1992 300SD 124K
Columbus Ohio
turner@greif.com

King 123, but King Diesel???
 

The issue is w123 Diesel, or so I thought... Best 300D? In MY OPINION, yes! While most will argue a newer 603 block is a better car (and in most cases it is) it lacks in soul and diesel aura. Basically, I don't find the shape as pretty as the 123, while the 124 is a beautiful looking contemporary classic, the 123 is just plain classic. It is the last of the old world Benzes, old world interiors and materials.

While they (123s) are harder to service (valves and what not) and not as fast (603s put out more power) they are louder, punchier and more like a diesel truck! I think they have more character, they epitomize the diesel car in America. While they don't go as fast, have bad drag, and are harder to service, the w123 has a special place for MANY mechanics/owners.

The curves, the chrome, the noise. It all counts in my book. I like to think about it like the WWII Bombers, B17 and B22. While the B22 was a better plane on paper, the B17 won the hearts and minds of all who worked on them/flew them, and came to symbolize an era. I feel the 123 does just that.

Because really, if I wanted a fast w124, I'd get a 300E- great economy, MUCH more power and NO TRAP!

Bill a turbo version of the 123 is made no stronger than the non turbo version.

Sw please show the specs that illustrate the hevier parts in a turbo.As far as the oil jets to the pistons,the non turbo has that.Best regards Michael R.

Sorry Mike!
 

Sorry Mike, you are wrong. It is known fact that the 617.952 block is a stronger, heavier block. The cc's are a little lower (due to the turbo) but the block'l lower end was reinforced, along with the crank, the cam and the main bearings. Mercedes HAD to reinforce the block due to the added stresses the Garret turbo charger added. If you were to put a turbo on to a lessor standard 617 block, it would blow it to shreds internally! While I don't have specs to support, I AM TELLING YOU the 616.952 motor is more stronger than a standard 617. Just stating facts! Give me time, I will get you specs!

randall,I defer to your knowledge.Best regards Michael R.

IMHO, here are the relevant facts I've gleaned:

The 617 turbo engine has a chain driven high output oil pump to drive the oil jets. The non-turbo engine doesn't have the jets, doesn't have the oil holes in the pistons, and a few other odds and ends. The non-turbo oil pump is driven off the IP.

Piston pins are larger in the turbo, bore is different (smaller or larger, depending upon exact engine), but the crank is the same.

I don't think MB "beefed up" the lower end -- I suspect it was originally stressed for a turbo, as the development engine (the C111 test car) was turbocharged at more than one atmosphere!

Peter

Bill:

I guess that is why there are those three numbers after the 617!

I have no idea -- they are all the same size as far as I know. Maybe deeper nitriding on the more powerful ones, but different alloy? Who knows. The only way to find out would be to check part numbers for the various 617.xxx engines and see if they are different.

Moot point for me, as I have a 615 and a 603!

Peter

FYI:

As it's been said already, the oil jets are non existant in the na engine. Have a look at the pictures below taken from page 45 of my 1982 sales brochure:

The circled area on the left illustrates the oil jet and the piston. The circled area on the right shows where the oil jets are located in the block. The picture below it (b&w) illustrates the na engine. I don't see any oil jets.

http://freeweb.pdq.net/waas/mvc-045f.jpg
http://freeweb.pdq.net/waas/mvc-044f.jpg

Also, from the PP/IMPCO catalog, it seems that the non turbo 300D and the 240D have the same part number for the pistons. If anyone has info from MB to prove that the na engines have oil cooled pistons, please post it, as it would be a learning experience for me and a lot of us.

Regarding the issue of which engine weighs more, page 7 (covering the 300D turbodiesel) of the brochure states:

"The turbodiesel transformation brings a 45 percent power increase, at the cost of less than five percent more vehicle weight."

I can't find anything in there that says the SD and D engines are different. I know the oil filter hosings are different. The crank might be the same in both but the one in the trubo is nitrided for increased hardness and fatiigue strength.

I quite enjoy the 120-mph speedo found on my 1983 300D. I had it at 110-mph the other week. The car felt as tight with the ground as it does at 80-mph.

I prefer the turbo-diesels. 1982-1985.

Turbo's and diesels are a natural together. Diesels are much more efficient with them. Now that being said, I have a NA diesel in my CD. Not having a turbo is not a good reason to not buy one, as these w123's are getting harder to find with good bodies. I really like this NA engine. Thought about building up a 952 for it, but it really does run to good, so I'm leaving it as is. I do like the better milage of the turbo's though. 28-29 mpg is about the best I can do .

Have a nice weekend

I am running three turbo diesels. Of these, my 1981 300SD, with 328,000 miles runs stronger than the 84 or 85 TDs I also own. Its a heavier car and gets better fuel mileage.

The lighted sun visor mirrors, the delayed courtesy light, etc upgrades starting in 83 are all nice, but to me the most valuable upgrade is the electric right hand mirror. MB should have done that from the beginning. There is something else MB could have done. The turbo could produce even more power if it didn't heat the rammed air. As Emeril would say,"Ben Ridge kicked it up a notch". I wnt for a ride in his INTER COOLED 300 a few weeks ago. As Jackie Gleason would say" how sweet it is". That puppy scoots.

On another note if we follow the example of Craig Reece and others like him, we may not have to go to Iraq this spring. Craig drove his 87 300TDT to my hobby shop this Saturday on BIO DIESEL. We worked all day until 9:30 at night, but just before he drove off back to Berkeley where he lives, we dumped 9 gallons of peanut oil into his empty fuel tank. A friend of his commercially cooks turkeys in peanut oil. We installed an Elsbett conversion which requires the installation of a heated fuel filter and different glow plugs and injectors. The documentation sucks. It is another example of someone knowing 2 languages but nothing about the subject. We figured it out, and the car runs great. He phoned me next morning and said he hit 90 on Interstate 80. I guess I'll have to convert my 83 wagon.

Peter

IMHO, the best 123 300D's were the ones that were missing one of the cyliinders, had a manual transmission, no automatic climate control, manual windows, manual sunroof, etc.

Actually these were called 240D's. Easy to work on, and no automatic transmission or automatic gadgets to break.

Have a great day,

yes and slower than sh#% also...turn the AC on and try to start up a hill or dart into traffic


Warren
1992 300SD 159K
Columbus Ohio

Larry,

You're talking basic transportation, and who wants basic transporation? I will agree with you on the 240D aspect. It was the work horse of the fleet. I have owned dozens and happen to have an 83 now. They are very good and dependable cars in places like where you live. I was in Dallas for a square dance convention a few years ago. We drove west out of Dallas to a nudist resort since I am a card carrying nudist, and I looked back when we were about 20 miles out of town. Dallas looked about two miles away. Talk about flat country. I don't take my 240 to places like Tahoe or Yosemite or Carson Pass where you have to climb to 10,000 feet. By the way I'll take mine with power roof, power windows, power mirror, and auto.

See ya larry,
Peter

It all depends on what you want and what you like. I have driven MB diesels for many years and each engine had some uniquness that made them special. My first diesel was a 1963 190D with a 1999cc engine. Very simple with minimal gadgets. Did not have a vacuum pump and was very easy to work on when you had to work on it. Very little power and you had to drive it hard. I never liked the 3 main bearings on the crank. IT made the car vibrate more IMHO. The following year MBZ came out with the 5 bolt main. The next car was a 615 1969 220D. Bullet proof engine with slightly more power and a great suspension. First time I experienced a 4 wheel drift. Next car was a 123 1979 300TD. Beautiful ride, great styling and nice chrome. Manual sunroof that was hard to open. Not sufficient power when fully loaded and heading to Tahoe. The next was a 123 300 Turbo. Great car, felt very light and handled fantastic. Great breaks. First time I drove over 110mph. Next came a 87 300SDL. Big car, handles like a big car, but plenty of leg room. The car always feels to big for me. Then came the 124 87 300TD. This by far is my favorite. Great power and comfortable to drive. Also very easy to work on. Seems like the engineers took more consideration into the mechanic. On the 603 engine and the 124 chassis. Any 124 car without a glove box is not for me.

Couple things I dislike about the 124’s:
1. Upholstery coming off the door pockets
2. Complicated climate control, but better than older cars
3. Battery location, when they leak the get on electrical stuff
4. Not enough leg room in the back
5. Eats brakes and tires no matter what brand
6. Front ends loves to go out of adjustment
7. Sounds system
8. Speaks covers in the back door, kids seems to pull them off
9. Electric antennae
10. Roof rack, you put anything on it and the paint chips
11. No cup holder
12. No cup holder
13. No cup holder

Anyway just my two or 10 cents worth.

Yes, the Dallas area is flat. When I was driving my 240D, I spent more time in the hills of Arkansas than I did in Texas. There was one road between Fort Smith and Fayetteville on which there was a series of huge caution signs that read; "CAUTION, HILLY AND STEEP.......NEXT 10 MILES........14 DEATHS IN THE LAST TWO YEARS...........DON'T YOU BE NEXT."

I drove that steep and winding road A LOT! Using gears it worked great.

If you are talking a turbo 123, yes it has a little more power than a manual transmission 240D. If you are talking a normally aspirated 300D, there is virtually no power gain over a manual transmission 240D. You have a theoretical 25% power increase, but you're forced to give that increased torque back to the automatic transmission.

If you think a 240D is slower than whatever you were referring to, I expect you have not driven a MANUAL TRANSMISSION 240D. They are not that bad.

The 300D's with all their automatic doodads to break, along with the crowded engine compartment are a total PITA to work on. If I lived in high altitude mountainous country, I don't know what I'd drive, but it wouldn't be enough to make me drive a five cylinder 123 car.

The only thing that would make me drive a five cylinder 123 car would be if it were the only thing between me and walking. I regret the day I bought the 300D for my daughter. Luckily, since that time, she has become a very competent stick shift driver.

If you don't have to be the one busting knuckles under the hood, and have all the work done by someone else, then I suppose it would be okay. I'm the one busting knuckles, so it's just not worth it to me.

Each to his own,

I have a few questions from the 13 items you have listed..but to start...no glovebox=dual airbag in a 124(or 126 for that matter)

but added storage between the fron t seats...

brakes,tires...I used to get about 50-55K on my tires when owned a 124 and about 25 K on the brakes...not bad in my opinion

battery leaking?....sounds like you needed a new battery

sound system...I don't any of the MB sound systems were any more than average until the 90's

cupholders?....I assume you now have a post 1995 car?
antenna...sold my 92 300D 2.5 with 208K on the clock..never replaced the antenna


Warren
1992 300SD 158K
Columbus Ohio

I have a 87 300TD and a 95 E320 Wagon. THe stroage compartment between the seats is to small to put the service booklet and the owners manual. It gets relugated to either the back seat pocket or the side pockets in front. Maps don't fit well. The glove box is truly missed. I have always felt that Mercedes did the easy and cheap fix and just did away with the glove box. Poor planning on their part.

I do a significant amount of driving in the mountains on steep roads and logging trails. No place for a 2 wheel drive Benz, but it works. Eats up tires do to alignment issues. Even rotated tires every 5k miles with no impact. I consistently get 35 40K on the tires and no more.

I also live in SF area and that coupled with mountain driving eats up brakes. My front rims always look dirty. THe brakes are easy to replace and I can do brakes and rotors in less than 1 hour. No need to remove hub assembly to get to the rotors as you do on the older Benzs.

Battery leaking=needs new battery.

This is a fairly obvious correlation. Still, when it happens, it only takes once and it starts deterioting the wire insulation and vacuum lines. THis happened on the E320 after 3 years and the acid was sucked in the vacuum lines. Not a well thought out design.

For whatever reason, the antennaes on my stations wagons don't work well if at all. Maybe it has to do with the location. Adjacent to the body where they may experiance more wind deposited debris from the aerodynamics of the car. Purely speculation.

Anyway, drive what you like. If it is a diesel benz in good shape and well taken care of, it won't let you down.

Wow!! Autozen....
 

"We drove west out of Dallas to a nudist resort since I am a card carrying nudist"
hehehehehehe!
Man, I can respect any MB owner but that is just a little too much information..... Doesn't the MB Tex stick to your butt when you're driving sans pants? RT

Rwthomas,

I was a passenger in a non MB. Also you don't leave a resort in the nude. When you enter the textile world, the rules change. Anyone who is not a nudist can't imagine how open and comfortable people can be when you bare it all. All trapments of social status disappear, and we are all the same.

Peter

Just poking fun at you dude. To each his own, thats what makes this country great. Lets just enjoy our Benz's. RT

RT,

I wasn't offended. I'm thick skinned. You have to be when you don't have any clothes to protect you.


Peter:D