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Mercedes 300D Suggestions

Hello all I am the owner of a 1983 Mercedes-Benz 300D Non-Turbo. While driving it last year the oil pressure suddenly dropped the temperature shot up and then blap blap blap bammmm! Blew a rod right out of the bottom of the block. I would like to fix it again to drive to college, any suggestions and price info? All suggestions appreciated.


  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Hmmmm.....well, you have a tough problem here in that fixing the engine is worth the price of the car, more or less.

    There are a few ways you can go.

    1. Used engine --these engines should be good for 250K or more if they are well-maintained. If you can find one that's still running to listen to before the yard yanks it out, all the better. A good Mercedes diesel starts instantly when cold. If it cranks and cranks, the engine is worn or something is wrong.

    2. I have seen used engines on Ebay, but of course you don't know when they might come up.

    3. You can just find another 300D. You often see very clean ones for $3,500 or less.

    good luck

    Shiftright the Host

    (I have one of these cars myself with 226K on it. I'm surprised yours blew up).


  • My mechanic told me it was a common mistake with my car the oil filler cap has a gasket inside it and " meine ist kaputt" in friendly words and it literally blew all the oil out of the top while I was driving.
  • haspelbeinhaspelbein Posts: 227
    ...of an oil leak out of the filler hole. (Cap wasn't on properly.) But my question: Didn't you smell that ? In my case, the oil dripped onto the engine block, ran down the side and was "cooked" quiet nicely on the way down. It was a rather smelly affair.
  • When I heard the terrible noise I got it into a drive and there was a terrible sulfuric smell, like bad eggs. Other than that...Well tomorrow I am looking at a MBZ 190E, I may just buy it instead of fixing the 300.
  • haspelbeinhaspelbein Posts: 227
    That would be a pity. They have a lot of character, and are truly a dying breed these days.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Yes, but who would put $5,000 in a $3,000 car. Many old 4-doors will die for this reason.

    I have been gathering parts for mine for over a year. I have three crates filled with hard to find items--no complete engine though! I'm not planning on replacing that.


  • haspelbeinhaspelbein Posts: 227
    Mr. Shiftright, the last thing I remember about yours was that your neighbors boat hit it during a storm ? Did his insurance end up paying for it ?

    I would agree that a $5K engine is a lot of money for a car that old. When faced with such a decision, I'm always trying to consider the overall state of the car (How much longer will the rest of it last ?) and how attached I am to this vehicle. If it will keep me from buying a new one, it may still work out, unless the car gets totaled somehow.

    But overall I agree, $5K is probably too much.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Yep, the boat owner's insurance footed the bill and the car looks great! Damage was $1,980 on the low bid, so that's a perfect example. I doubt seriously that I would have repaired the car out of my own pocket....maybe....$2,000 is right on the fence, I'd almost be tempted to put that money towards something else.


  • I was on this website helping a friend and I stumbled upon this conversation...

    I have an 82 300SD (214K) that has difficulty starting in temperatures below 15 to 20 degrees (which unfortunately is common during Iowa winters). Note - when the block heater is used it will always start no problem.

    What I'm trying to figure out is if this problem starting in cold temperatures is normal / expected or if there is some sort of fix. One dealer told me there were different glow plug types and that I might try 'hotter' glow plugs.

    After reading through the earlier messages, perhaps 'autojunkyjosh' would like to buy my car. It's very clean and he could get the whole car instead of a replacement engine - and have a lot of spare parts.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    Diesels often have trouble starting in cold weather. There are some possible solutions

    1. Using a very good anti-gel + conditioning additive to the diesel fuel

    2. Replacing the glow plugs and checking the glow plug relay

    3. Making sure you have a very strong battery

    On my car, I rigged up a direct line from my battery to the #1 glow plug (which is in series with all the others). On very cold days, I would connect the battery directly to #1 glow plug (with an inline fuse installed, 80 amps) and in this way I can leave it "glow" for as long as I need to start the car. Works great. Of course, you MUST remember to disconnect that battery wire once the car has started.

    I use a Redline additive, but any truck stop would have equally good additives. Cheap STP stuff in o good, you want something that is not only anti-gel but a "cetane enhancer" and an injection nozzle cleaner. It's not cheap but it really helps a diesel perform better.


  • lancerfixerlancerfixer Posts: 1,308
    Where in IA are you located?
  • Oskaloosa, Iowa.
  • I know that oil viscosity plays some part in the difficulty with starting in cold temperatures.

    I generally use 10-30 in winter months and 20-50 in summer months.

    Someone suggested I go to 5-30 in winter since the lower viscosity should help with the starting. But, I have never been comfortable with 5-30 fearing it will break down rapidly - especially in a diesel engine which seems to be so much harder on oil than a gas engime.

    Any thoughts on the oil issue?
  • lancerfixerlancerfixer Posts: 1,308
    I recently moved to Cedar Rapids...have NO clue where Oskaloosa is... :-)
  • It wasn't long ago that I moved to Oskaloosa. The joke I tell people is...

    Do you remember Radar O'Reilly from M*A*S*H ? Radar was the stereotypical small town boy from rural America. He was from Ottumwa.

    I now live in a town that Radar would consider small !

    (Oskaloosa is about 30 miles Northwest of Ottumwa and about 60 miles Southeast of Des Moines.)
  • Mark how much do you want for the 300SD, I am actually looking to buy another Mercedes. My latest find a 86 560SEL. My e-mail is Thanks for everything Mr. Shiftright. I am still open to suggestions.
  • frankievfrankiev Posts: 1
    Hello everybody. I've enjoyed the discussion. I have an old bronco and a 10 day old son, hence I've been looking for a more family friendly car. I've come across an '87 300 turbo diesel with 199K miles. They say they have all the maintenance records and has had a recent engine overhaul (valves, timing chain, vacuum pump, drive belt, rear main seal)and new brakes. I live in Atlanta, GA so our winters are not that cold. Any recommendations or warnings? Thanks
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    That's a hell of a lot of miles. It may have life left in it, but I hope you are buying it very cheap. Even with an engine overhaul, the rest of the car still has 199K, as does the bottom half of the engine. I'd certainly drop the transmission oil pan and have a look, and lift the car and check the front end, driveline and rear CV joints. These are rugged cars, and not too hard to work on, but not cheap to fix either. Oh, check all the heat and a/c functions thoroughly. Play with everything electric 10X.


  • Mr. Shiftright, when you have time please comment on my oil questions in #14 above? Recently someone recommended that I use motor oils available at truck stops (that are commonly used in semis). Thanks.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,413
    I'm no fan of 5 weight oils, no. I think a 10-40W is just fine and especially oils formulated for diesels.. There are additives and block heaters for easier diesel starting, I would not risk using oils that try to do too much at once. Your little diesel is not a Peterbuilt. Those engines are HUGE. They have a lot more friction to contend with and lots more oil capacity to churn through on cold starts.


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