300d 1987 - PeachParts Mercedes-Benz Forum

#1 11-03-2002, 09:39 PM

Does anyone have experience with these motors? I'm trying to find out if these had any problems. I'm looking at one to purchase. It is in very good condition with 101,000 miles on it. The overall appearance is excellent. The motor seems to run very well. I do recall some problems with a couple of years of the Mercedes diesel. Does this one present a problem?

Thanks for your help,

Jim

#2 11-03-2002, 11:05 PM

Not really, it's a great engine. Just don't overheat it or you may crack the head. In about 50,000 miles you should change the vacuum pump as preventitive maintience.

Ken300D · #3 11-03-2002, 11:14 PM

The general consensus is that these are among the good diesels.

I have one running like a top at 350,000 miles, used daily in the commute and I get about 30 mpg.

The only thing to complain about compared to the old all-iron diesel engines is the aluminum head. If overheated they can crack. But the car has shown no tendancy whatsoever to overheat, unlike my 1982 300D at times.

The other thing the 1987 does that the 1982 diesel doesn't is throw out a lot of unburned diesel smoke and run roughly for the first two minutes after a cold startup. Later MB diesel engines kept the glow plugs on for awhile after the engine starts, keeping the engine running smoothly. Mine starts smoothly with no smoke, and then about the time the glow plugs get a chance to cool off - out comes the smoke and a little rougher running. Not a problem to me but it can be disturbing to new owners not used to diesels.

I would buy the same car over again without question.

Ken300D

#4 11-03-2002, 11:17 PM

Wow, 350K already? I remember when you got it off ebay at 310K.

Ken300D · #5 11-03-2002, 11:29 PM

Yes, its been about a year now - it was a little under 325k when I got it. Many more years and miles to go I hope.

Only thing to worry about on a "good series" MB diesel is rust - that will take the car away from you before an engine failure in the majority of cases.

Ken300D

#6 11-04-2002, 12:17 AM

Is the 300d 1987 motor the same as the 300sdl's? Thanks again for all of your input!!

Jim

speedy300Dturbo · #7 11-04-2002, 03:03 AM

They are fast too... and much more refined than a W123 diesel.

#8 11-04-2002, 05:12 AM

Yes it is.

psfred · #9 11-04-2002, 10:22 PM

I've got 178,000 miles on my 87, have had it a little over a year. No engine problems except some bad pressure valve seals in the IP when I got it.

However, I suspect it has a new head -- brand new radiator and some oil residue in the coolant tank. Or the head it bad and it hasn't started using coolant yet.....!

Nice car, runs wonderfully, got 34 mpg a couple weeks ago on a road trip.

Peter

CBGraves · #10 11-05-2002, 02:10 PM

I just bought an '87 300SDL. I'm getting no where near 30mpg, even on highway driving. I suspect I've got some vacuum leaks that are a potential contributor to poor mileage. I replaced a few rotten lines yesterday and the car at least seems to perform better - smoother accelleration, smoother shifts, etc. I haven't driven enough, particularly on the highway to know for sure. Anything else that I should check?

md21722 · #11 11-05-2002, 02:35 PM

You will probably get 28 max in the 300SDL - its heavier.

-brian

CBGraves · #12 11-05-2002, 02:41 PM

Thanks Brian - I was hoping to get about 27. Not quite there yet. Would appreciate any comments about things to look at to optimize mileage.

In looking for my car I don't recall ever seeing an 86-87 300D for sale in the Dallas area. Are they more rare than the 300SDL?

md21722 · #13 11-05-2002, 03:01 PM

Poor diesel fuel can reduce economy upwards of 20%. I see a varation from 25-30 with my '87 300D depending on fuel.

-brian

gsxr · #14 11-05-2002, 03:34 PM

Jim,

They are great cars & great engines. But there are certain things to watch out for on the 1987 diesels specifically. Here is an article that covers most (but not all) of the things to check:

http://www.mbz.org/info/articles/misc/used124/
(Note: The site is down right now and results in a 404, please keep trying, should be up in a day or three... MBZ.org had a drive crash and they're re-loading.)

If you buy it, I'd change the vac pump ASAP. Typically they last 150kmi but I just heard of one blowing up at a little over 100k. The originals had a flaw, the new ones are OK. The only other significant thing (also detailed at the URL above) is the operating temp. The radiators tend to plug quickly due to the internal tube design, and the fan clutch may be shot after 15 years. The operating temp should be 100-105C absolute maximum, and that's in blistering summer heat. If you see those temps in the winter, or anything higher than that, the cooling system will require repair (new rad/clutch/tstat/whatever). Because as everyone else has already said, if overheated you WILL have head problems! Oh, also have the trap oxidizer removed (free recall) if it's still there. More info in the PDF's at this URL:

http://www.meimann.com/docs/mercedes/

Regards,

psfred · #15 11-05-2002, 08:18 PM

Bad alignment, crappy tires, and dragging brakes will all reduce milage considerable. So will being unable to keep your foot out of the accelerator (difficult, since these cars respond so nicely!).

Ditto for late/early injection timing and a plugged trap oxidizer. You will know if the trap is still there -- lookes like an oversized stainless steel football above the turbo. Replacement is a squarish pipe with heat insulation around it.

I'd check tires for obvious signs of misalignment, brakes (a good idea anyway, who knows what was done before) first, then the injection timing. Takes a special tool, alas.

New fuel filters, a bottle of RedLine or Diesel Purge, nice fresh synthetic oil, and a high speed road trip won't hurt, either.

My brother (his wife, really) gets about 27 in their SDL, about 29 on the road.

The 300D with the 603 was sold only in 1987. No diesel in 88, I don't think, but all later models are the 2.5L 5 cylinder 602. Less performance, better milage, same lovely car.

Peter