Hey guys,

I'm going to check out an '83 300D Turbo tomorrow. It's got an auto trans (which will probably change if I purchase it) and it's got 308,xxx miles on it. Normally I'd be looking for something with lower miles, but the price is right, particularly for Portland. Besides, it will last till the end of time if I take care of it, right?

Besides the obvious stuff like good records, no rust, electrical and vacuum stuff working, and the car driving well, what should I be looking for and what should I be watching out for in a 300D? What are good indications that the car has been taken care of when I look under the hood? What are indications that it hasn't?

Any advice would be greatly helpful.

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-1991 Ford Ranger: multicolored and the clutch is gonna die.
-WTB w123
-Aspiring Biodiesel homebrewer

search

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1984 300D

mutant is right, seek and ye shall find.

That being said, I recently bought two of these puppies, and I recommend checking out the following:

- the CV boots on the rear axle. These are not fun to change.
-oil leaking is a pain, but probably unavoidable in that mileage bracket.
-get the VIN and check it on the russian mb club online VIN checker (search the forum, and you'll find a link)
-definitely drive the car. check for clunking as the transmission shifts. This can indicate anything from vacuum problems to deeper transmission issues
-check out the vacuum system. lots of stuff on these cars runs off vacuum, including the door locks. after your test drive, pay attention to how the car shuts off (shut off valve runs on vacuum). if it is sluggish to shut off there are probably vacuum issues. then get out and lock and unlock the car until it can't do it any more. This will indicate how well the vacuum resevoir is holding vacuum, and if there are any brutal leaks in your door lock system.
-press all the buttons you can find, and see how stuff works. (windows, lights, climate control, etc.)
-lift up the floormats (esp. the rears) and check for rust. this may indicate a water leak into the body (not uncommon)
-common places for rust: hood hinge wells, rear floor pans, bottom of doors, wheel well areas, i have heard that the rear strut tower tops go on the sedans ( i only have wagons), trunk seal area, all window seals
-if you can, have a look at the air filter. if it looks super manky, probably an indication she hasnt been looked after super well.
-rusty exhaust might be a pain in the butt
-there is a small clear plastic inline fuel filter on the driver's side of the engine have a look there-if she's all bunged up, maybe think twice

i dunno

good luck, i hope you buy it

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George

Vincent: 1984 300D - 255,000 miles - NEW!

Wilbur: 1991 GMC Sonoma 2WD 2.5L 5-speed 250,000 km (top secret project)
Pancho: 1992 Mitsubishi Pajero SWB RHD 2.5L intercooled turbodiesel - 215,000 km

See

http://mbdieseldiy.tripod.com/dog.htm

and

http://mercedes-w123.net/buyers_guide.htm

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Sunroof repair is expensive (but you can live without a sunroof). Ditto cruise control. Harsh/extremely firm shifting may indicate a vacuum problem. Check the jack points for rust. Your car has the "ACC II" climate control which is good (better than the old servo system) but it is still a complex system that is hard for a newby to understand. At least see if it heats and cools and that the fan works and all that. Check the brake fluid and the power steering fluid; if either one is black, indicates that routine maintenance has been skimped. Red power steering fluid is ATF, which is OK but not ideal, should use correct fluid – gives you a feel for how important it was to the owner. New PS fluid is clear, as is new brake fluid. Check to coolant in the expansion tank. Green is not correct MB coolant, again marginally OK in a 617 since it has a minimum of aluminum parts but the proper yellowish MB coolant is better – again, gives you a feeling for the owner and how much he cares. Make sure it has a "big" battery (I don't know the group # off the top of my head), some people skimp by putting in a little gasser battery.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

shop manual, you are going to need it
a heated garage.
a larger backyard/driveway......these things are addictive
a parts car
NOBODY can have just one

someone who thinks it is worth alot more more than you paid
for it...........and wants to buy it

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81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

1. blow-by gasses from a hot engine. Put it in park after a drive and leave it idling. Open the hood and open the oil filler cap, setting it over the hole. If the gasses make the cap dance around or jump off the hole, don't buy that car.
   
   2) cam shaft wear. With the engine off, open the oil filler cap and run a finger over the front cam lobe. It should be perfectly smooth. If you feel scars or tears, don't buy it.
   
   3) While driving on a safe straightaway with no traffic, put the car in a lower gear and get the rpms going high with the engine locked into gear. Release the pedal and let the car slow down for ten seconds and then punch it while looking in the rearview mirror. See a lot of blue smoke? Don't buy the car. The smoke is likely the result of engine oil getting sucked past the valve guides as the manifold pressure increases.
   
   4) Test the compression. 0-62mph times for a turbo wagon are 18 seconds, 22 for a non-turbo.
   
   5) does the fuel level guage work? If not, there might be a lot of fuel fungus in your tank. It is easy to clean, but easier if you drain and pull it. If the fuel hose rubbers are old, they should be replaced (sent, return, tank screen and vent lines). The hard lines can be blown out with compressed air.
   
   6) Does the odometer still work? They are very easy to break. Just pushing the trip odometer button while the car is in motion will break the odometer Frown If it doesn't work, ask for paperwork to confirm mileage. If they don't have it, you should offer them less.

The big thing with any diesel is compression. If the compression is low the engine will be hard to start. So any car that you look at make sure you start it when it is cold. Make sure the owner hasn't warmed it up before you've gotten there. A hot diesel with bad compression will usually start. A cold one with bad compression won't. Once the engine is up to operating temp unscrew the oil cap and let it sit there. If it sits there and jiggles around a bit the engine is still in pretty good shape. If it blows off and is spouting oil out don't bother with the rest of the car. The engine is pretty well worn. What this is telling you is how much blow by there is. It is indirectly telling you how worn down the piston rings are.
These cars like to rust in the hood hinge area and the rear wheel wells. This is due to people not cleaning the drains out which mean water collects. So look in both of those places for rust.

This is all great stuff, guys. I'll probably print out the thread and bring it with me. I'll update you in the next couple of days!

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-1991 Ford Ranger: multicolored and the clutch is gonna die.
-WTB w123
-Aspiring Biodiesel homebrewer

ACII is the evil servo system. ACIII is the CC which you are describing.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

If it dances, its still okay too. As long as the cap stays on, its a decent engine. I have yet to see a 617 without some blowby, including a few with under 150k. Its a part of normal wear.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

Yep, blowby is normal. That is, some blowby.
Excessive blowby is when the cap blows right off when loosened, or if it looks like a freight train of oil vapor when the cap is off.

In the Northwest, you have different kinds of rust than some other parts of the country. But I'd put rust right up there with engine problems. If not higher. Putting in new floorpans is either a real pain or expensive. And the sound deadening material can hide a lot if it. Bring a hammer and tap around the corners of the floorpans and around the jack points. Should be a solid thunk. Crusty sounds indicate a lot of work. Any bondo on a car and I'd be walking. Most people's rust repair can lead to real problems.

Best advice is: bring along a friend who knows these cars well, and/or take it to a mechanic. Best 100$ you'll ever spend, especially since you know what you'll need to fix first. And there WILL be something to fix.

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This is something I wish I would have done take a voltmeter with you and check to make sure your car is making the right voltage, trust me nothing will irk you more than having a car you just bought have a bad voltage relay!! Also look at the flex disc and the center bearing. Also if it passes the oil cap dancing test and still has a rough idle there is a very very good chance that no one has done either a diesel purge, vavle adjustment on it in a very very long time.

This is not true in a diesel. In a gasser when you let off the throttle the manifold vacuum will shoot up and oil can be pulled past the valve stem seals, thus creating smoke. On a diesel there is no throttle plate (except on some goofy 240Ds), and thus no manifold vacuum.

This test does not have to do with compression as much as it does overall engine tune. Those times seem a bit high too, I would say a 617 turbo should be around 15 seconds 0-60 and a non-turbo around 19. The 240D should be around 22.

A better test for fungus would be looking at the clear primary fuel filter. The fuel senders can get stuck from many things besides fungus, and even if is is stuck it will still register some level so it would be hard to tell if it was working on a test drive (unless it is a really LONG test drive)

Good point about the Odometer, but I think the resetting of the trip odo when the car is moving is a myth. They are not THAT fragile.




Both good points. Check the under the plastic liner at the front of the trunk side "pockets" for rust, that is probably the most common area. Also look in the vicinity of the battery.


Let me know if you need a hand checking it out.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Ahhh – right. I was thinking that the manual system did not get an ACC number, since it is not "automatic." That would make the 'evil servo' system ACC I and the newer system ACC II. The FSM, however, calls the manual system 'ACC I.' Maybe 'ACC' means something else in German (like 'ABS'). Thanks for the correction.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Sorry to ask this but a car can be hard to start because of other reasons right? The car I just bought had very little blow by but still took a few trys to start I assumed this was due to the glow plugs or the poor voltage the battery was putting out, or the fact that the car hadn't been started in a while 3-4 days, but was I wrong? again sorry to thread jack.