Questions about OM617 - PeachParts Mercedes-Benz Forum

dieselmania · #1 11-14-2017, 07:07 PM

Drove a 1984 300SD Turbodiesel today with a claimed 89,000 original miles on it. Overall in pretty decent shape with a bit of sun fading to the exterior plastics, a little checking of the still shiny paint and one tear in the pass seat. Oil leaking from valve cover and crankcase ventilation valve, transmission fluid leaking at radiator cooler fitting, original Becker radio not working seller says it's the antenna which doesn't raise but there is a new one in the trunk ready to install. The usual cracking of the console wood laminate and one minor crack in the dash. Some new suspension parts in the trunk not installed. AC is ice cold which is a big deal where I live, although it was only 88 outside when I drove it. Asking price is $8,500 which is actually in the middle range of what NADA says although I think it is high given the number of issues.

The big question, I am used to my OM603 which has a very smooth idle. This one does not, you can actually see the hood shaking and you can feel the "jiggle" in the seat at idle with the AC on. Not being used to the 5 cyl I wonder if this is normal?

Rogviler · #2 11-14-2017, 07:13 PM

It should be pretty smooth. It's probably motor mounts or the air cleaner mount. The air cleaner mount in particular can jackhammer through the whole car. Both being bad would definitely rattle your teeth. I'm sure you'll get three pages of suggestions of what it COULD be, but the only way to know for sure is to do some further investigating. That wouldn't scare me off, certainly. My wagon would barely move under its own power and I wasn't scared off though.

-Rog

rocky raccoon · #3 11-14-2017, 07:41 PM

I think 8500 is high with those issues. All of those problems are easy DIY on that car but I would suggest to the seller that you would have to take the car to an indie mechanic and an upholstery shop. Use them for bargaining point to get the price down to at least $6000.

The OM617 will probably never be as smooth as your OM603 but should be smoother than you describe. Ask when the last valve adjustment was done. Should be every 12 to 15 k miles. Also a DIY. The vacuum pump is normally a little rackety so don't mistake that for valve noise or rough running.

They have no pcv, just a hose from the valve cover to the air cleaner assembly. Visible oil around that connection would be a good reason to check for blow-by. Remove the oil filler cap while engine is running. It is o.k. if it does a little dance just sitting on the cover but if it flys out of your hand, there are blowby issues. Many such issues are corrected with the valve adjustment but there can be bigger problems.

Good Luck! Pix would help.

dieselmania · #4 11-14-2017, 07:47 PM

Quote:

Originally Posted by rocky raccoon

Pix would help.

Here's a link to the CL ad. I was mistaken on the asking price, it is actually $8,900. And the claimed mileage is actually 86K. The seller is motivated however and said make an offer. He did say a dealer drove down from Phoenix and offered him peanuts for it. The good thing is I am in no hurry having 4 running vehicles already, sometimes if you're patient the price goes down.

https://phoenix.craigslist.org/evl/cto/d/1984-mercedes-benz-300sd-5/6351589279.html

dieselmania · #5 11-14-2017, 07:55 PM

Good idea checking the blowby....I didn't think of that. I didn't think to ask for service records either....haven't bought an old car in a long time.

rbtoj · #6 11-14-2017, 08:15 PM

The idle shaking you describe could be a number of things, but all are DIY'able (with the exception of low compression).
One note: on the w123 you have to manually rise the idle when the car is cold or when using the AC (there is a knob on the dash for it). If you don't the idle gets quite low and shaky. I don't know if it is the same on the w126.

dieselmania · #7 11-14-2017, 09:22 PM

Forgot to mention, the car was purchased new in Germany. It was brought to the states at 4,000 miles by the original owner. It was inherited by the original owner's heir who in turn sold it to the current owner.

rocky raccoon · #8 11-14-2017, 10:03 PM

rbtoj: Not on the '84. It is a turbodiesel.

rocky raccoon · #9 11-14-2017, 10:11 PM

Looks pretty nice. I think a little effort can clean up the running issues. Worst case would be injector problems, probably new nozzles and a balance which usually comes up every 110k miles anyway. Serious engine issues are almost unheard of with OM617, particularly with that low a mileage.

BTW, my '83 coupe has 342000 and is my daily driver and long distance car.

eatont9999 · #10 11-15-2017, 11:28 PM

I believe that car could have 86,000 actual miles judging by the condition. The cluster does not have spotting in it from long-term exposure to the sun. The car was kept covered for most of its life, I can tell. I have only seen one dash cluster in that good of condition and it is in one of my cars now. It came out of a 1991 300SE.

Bengoshi2000 · #11 11-16-2017, 06:44 AM

I know you're in AZ where rust is a mythical beast, but look on the undersides of the doors and along the sill of the rear window.

t walgamuth · #12 11-16-2017, 07:22 AM

The 617 has a definite hop in its movement at idle. If you have not seen one before its hard to believe it is running fine.

The filter mount will cause a tinny clanging and the motor mounts will sound like someone is applying a jackhammer to the frame so they both are distinctive.

The normal hop does not make any noise.

BillGrissom · #13 11-16-2017, 10:03 AM

Don't know what the owner considered a "peanuts" offer, but I wouldn't offer more than $4000. For $8900 it would have to be super-primo condition, like perfect paint. All things mentioned sound like they could be easy fixes. If so, the owner should fix them. Otherwise, some could be killers like an engine with low compression. The seller may have information which you don't, which puts you in a poorer negotiating position. It could cost you much to obtain that info, all for a speculative buy. At a minimum, perform the simple blow-by test (watch air puffing from oil-fill hole, see youtubes). Even better is to agree on a price (in writing), w/ you paying after a compression check at a garage or drop the deal if <*** psig in all cylinders (say 380 psig).

I often see people first advertise high on craigslist, because free so aim for the moon and hope to snag a sucker. You often see the same car months later in ebay auction sell for 1/4 the cl price.

dieselmania · #14 11-16-2017, 11:18 PM

I think I will let it go. The paint is not that great and you can see they worked hard on it to make it shine for the sale but still a lot of defects and checking under that shine. It was obviously kept outside. The oil leak bothers me a bit and maybe it is more than just the crankcase vent, the frame member directly under the engine is soaked in oil. It is possible it needs a valve adjustment but if so that says it was neglected as far as service, probably while the heir owned it. I am sure most of this can be easily taken care of but I don't see the seller coming down much on the price. There are a lot of these cars popping up on CL all the time, I'll just keep watching. Dark blue is not really good in Arizona anyway.