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  #1  
Old 11-19-2017, 07:47 PM
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Question for the 617 veterans, would this knock scare you away from buying this car?

Hey Folks,

Quick question... I am interested in a car listed on local craigslist. its a 84 300td
with 295k miles - no rust (so the seller says) in decent shape.

Heres the catch, the seller posted a video of it cold starting and the motor has a knock I think is concerning. My 82 616 with 150k is pretty clattery on cold starts, but I presume its injectors nailing since it comes and goes very sporadically for the first like 10 seconds of running and then goes right away as the car idles better. I also think injector nailing and engine knock are quite different noises.

I have heard a number of 240Ds that are quite clanky and clattery with many miles on them but honestly haven't been around many 617 turbos.

Heres the ad: https://jerseyshore.craigslist.org/cto/d/1984-mercedes-benz-300td-w123/6379695854.html

Heres the video: https://youtu.be/ShxybdMEbP8

If the seller is on here please don't take offense... just doing my due diligence !

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  #2  
Old 11-19-2017, 08:33 PM
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thats not an injector nailing its metal on metal. it could be something in the valve train as it doesn't sound as deep as a rod does when it goes. if you go take a look look at the blowby and see if the sound resonates in the intake or if you remove the oil cap.
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  #3  
Old 11-19-2017, 08:38 PM
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Don't buy it, find another wagon. That's not normal and you would need to address that immediately. The price is too high with a engine problem.
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  #4  
Old 11-19-2017, 08:39 PM
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Definitely sounds mechanical in nature. Possibly a wrist pin? It doesn't sound like injector nailing to me.
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  #5  
Old 11-19-2017, 08:41 PM
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Would anyone want to suggest a reasonable price for the car with the motor noise?
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  #6  
Old 11-19-2017, 09:08 PM
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An engine rebuild would cost at least as much as the seller is asking for the car. Body is not perfect. Maybe $1000 and then try and find a good used engine?

If I were selling my 85 with perfect running rebuilt engine, I wouldn't hope to get 1/2 the asking price for that car. (It's not for sale!)
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  #7  
Old 11-19-2017, 09:46 PM
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Might be a failing vac pump. Nothing to sneeze at.
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..I also have a 427 Cobra replica with an aluminum chassis.
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  #8  
Old 11-19-2017, 10:05 PM
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spun rod bearing?
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  #9  
Old 11-19-2017, 10:39 PM
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Usually injector nailing has rough idling/running associated with it. The ad says valves were adjusted, so unless one was not adjusted properly, I would rule out a valve/follower problem. It was also stated that the injectors were replaced (this can rule out or confirm injector nailing depending on if the injectors were rebuilt properly). A Diesel Purge was done as well. Although it is hard to tell exactly what is causing the noise on the video, my money is on a wrist pin. I had an engine that I was sure the sound was coming from the valve train, but turned out to be a bad wrist pin. After pulling the head, I could see where #1 was just kissing the head. Either way, the car is not worth the asking price with that many miles, and even without the knock (in my opinion).
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  #10  
Old 11-19-2017, 10:41 PM
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When people post a video so you can hear how it sounds and they talk through the whole thing.

-Rog
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  #11  
Old 11-19-2017, 11:00 PM
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With TW ,Vac pumps give out at the roller bearing armature ,the sound is undetectable where its coming from when this does occur ,lends itself that its the motor ,it is the bearing itself that fails ,you then end up with the armature piece riding around on the drive surface of the pump landing (roller coaster looking piece )and making this exact noise ,if you wait long enough the armature fails and ends the guess work for you ,spills into the chain gallery.Had the same noise ,2 different cars ,saved both with a replaced vac pump.Once you have it off its very noticable.
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  #12  
Old 11-20-2017, 02:51 AM
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Bottom end noise, rod i'm guessing.

Don't understand how a low millage OM617 can produce such a horrendous sound. Why and how did it happen?

It probably has triple the claimed millage
Ran it low on oil
Ran the wrong oil
Never changed the oi

It doesn't add up.
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  #13  
Old 11-20-2017, 09:38 AM
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The fact that the noise went away so quickly when starting from that cold temperature would make me think it could be a "piston slap". The piston is the first moving metal object in the engine that heats up from combustion with the exception of the valves. As the piston expands from the heat, the noise diminishes rather quickly.
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  #14  
Old 11-20-2017, 11:03 AM
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Just from seeing him start it up at ~20 degrees and then by the end of the 2ish minute long video he revs the thing up quite high from the sound, I realize my speakers may not be as accurate as my ears think, and by that time oil has reached everything, but man I try hard not to thrash my stuff much until its all warmed up good.

Knock sounds bad. I had the knock in my blue car I determined to be a worn out cam and followers, I replaced the vac pump as well, but it was not nearly as noticeable as the sound this car makes.

I sure wouldn't give the asking price for it. I gave 1300 for my grey car, could have driven it home but was told it had a bad transmission, so ended up towing it, the blue one was given to me because of the knock.

I love these cars, but they are not nearly as valuable monetarily speaking as most people seem to think, at least not to me.

On the other hand, what would it take for me to sell one of my cars? A lot more than its "worth", because I'm attached to them.

EDIT: adding a few more thoughts below:
He says he fixed some areas where clear was peeling, one looks like the antenna area, which in my experience usually rusts out bad, the paint doesn't match at all, possible rust repair?

Drivers side light/hood/fender doesn't line up right. also interesting that all the lights, grille and that was replaced. possible collision damage?

The underneath does look quite solid. i'd poke it though, as my grey car looked like that but your finger would go right through it

Was forsale in NC as found via googling vin number: http://classiccarsmarks.com/mercedes-benz/98729-1984-mercedes-benz-300td-base-wagon-4-door-30l.html
Seats have been replaced, is apparently grey market car, trans was rebuilt but slips 1-2.

Here it was in california for sale: http://findclassicars.com/mercedes-benz/108392-classic-1984-mercedes-benz-300-td-wagon.html

has only done 5k miles in the past 2 owners worth from CA to NC to NJ? if they drove it between those places, that's 3100ish miles.
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1982 300D (w123, "Grey Car")
1982 300D (w123, "Blue Car")
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1997 Dodge Ram 2500 12V Cummins
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Previous Vehicles:
1995 E300D, 1980 300SD, 1992 Buick Century, 2005 Saturn Ion

Last edited by Jarod; 11-20-2017 at 11:19 AM.
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  #15  
Old 11-20-2017, 11:37 AM
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I'd only buy it if the price reflected a car that I would have to replace the motor with a good used one.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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