Today i took my 87 300 sdl to my local repair shop, to have a tapping sound checked out. i was advised that it was a spun bearing causing the sound. The other day i was told it was either the cam tapet or a piston problem. what should be my next step. what should i expect to pay for a replacement motor worst case. The sound increases while driving and decreases at idle. The car still has power and is still smooth no smoke at all. thanks in advance




87 300sdl 340k

at the mileage shown (340K) its probably in need of other work so unless the head has been replaced (very possible) and knowing other factors would help decide if putting the $ into the bottom end would be all that is necessary.

I would look for a replacement engine as the cylinders are probably worn excessively at that mileage and rebuilding a OM603 gets very expensive beyond just replacing the head (thats a best case scenario, worn cylinders or spun bearings are the last thing you want to have happen.

There have been core engines (short blocks) sold for cheap after the heads failed. I've had the opportunity to score one on two occasions but I passed on the thought of tearing them down bit in one case I am sure the crank was good the other had a cracked block from a failed vacuum pump.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Rebuilt OM603 engines from reputable sources such as Metric Motors are about $8000. I agree with DD that a good used engine is your best bet. Maybe you can find a 300D or 300SDL with a poor body/interior but a nice engine with 200,000 or fewer miles.

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

I do not know if your model of Engine has the Separate Small Oil Pan like the 617 type Engines do but if you did spin a bearing I would expect to find some metal fragments or flakes at the bottom of the OIl Pan. They might or might not come out during the draining of the Oil.

If it is a Rod Bearing going bad sometime if you loosen each Injector Hard Line Nut and retighten them one by one; the tapping sound may deminish or change on the Cylinder with the bad Rod Bearing.
An additional sign of a bad Bearing can be fluctuating and/or lower than normal Oil Pressure.

If it was not actually taken to a Mercedes Dealer to get an opinion I think I would take it to one and see what they say it might be. You do not have to have the work done there.\

You might want to read this thread and see how decieving Engine sounds can be.

Please, not a spun bearing 92 300D
http://www.peachparts.com/shopforum/showthread.php?t=253673

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84 300D, 82 Volvo 244Gl Diesel

post a sound clip of the motor. if its running fine it will either (a) be normal noise or (b) let you know soon enough if something is really wrong.

hopefully you are just hearing an old diesel benz motor...

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Paul
Benz-less
I need an SDL !

If you really want to know if there has been damage to the bottom end, get your oil analyzed by a reputable lab. Your local heavy equipment dealer can steer you to the nearest one. Nothing can hide from oil analysis techs. Cheap and definitive. Cheers Dan

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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators