Okay, so it's been very, very cold in VA over the weekend and in the single digits once or twice at night. I attempted to start my 84' 300SD in the morning, turned over once or twice then...nothing battery completely dead. I Called the mercedes roadside assistance for a jump, he showed up, attempted to charge my Sears Diehard battery (which was a piece of junk to begin with) and it took 18 minutes showing very little charge. So fine, I had enough and asked the fella' to replace the battery with the new mercedes battery he had. Boom! 4 minutes later car started right up. Next he recommended that I put some karosine/gasoline in the car to keep the diesel from geling overnight, hence I put in one gallon. I drove the car for a few minutes and next I start hearing these random clanking and pinging sounds from underneath the hood. In dispair, I'm thinking ohh' Lord no!! What have I done? I drive home park the car and wait for a few hours. Midnight, I decided maybe I should top off the tank with more diesel and purchase an additive in case some unknown problem should arise. The pinging persists almost embarrsassingly so at the stop light. The next moment, the pinging and clanking stops all the while the car is excellerating, and running smooth even at idle, but as the pinging and clanking stops....all of a sudden the dashlights come on, GAS, BATTERY, SEATBELT and the steering gets tough....WHAT IN THE WORLD JUST HAPPENED? Can someone please help..Is this due to the gas, the new battery, a dead or weak starter or alternator..camshaft pulley? Any ideas?

I had a similar problem with my 93 300E 2.8. It turned out to be the alternator. Driving along the engine would run rough, then get well, then all the lights in the dash came on a few miles before the battery was too weak to operate the car. Replaced alternator (had it rebuilt about a month before the trouble.) Prior to that it would let battery die, and all the lights would come on occasionally and then get well. After the rebuild, the battery was staying charged, but still got the craziness with the lights. All this happened after I replaced a weak battery that wouldn't hold a charge. Maybe it killed the alternator by requiring charge all the time. Final cure was a new Bosch alternator. No problems since. Take it to a good tech with the right diagostic tools and they can confirm the problem before you buy one. They aren't cheap!

happened to my 260E as well. it wasnt the alternator all together, just the part attached to the alternator whose bushing went bad. but in either case probably is your alternator.
good luck with it.

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Whether you think you can or cannot, Either way you're right!. by Henry Ford.

Started the car up this morning to take another look. whoooa! NONE OF THE BELTS ARE ROTATING! Could this still be an alternator?

Could be the worst of all...CAMSHAFT PULLEY may have failed..meaning engine may have to be pulled out...$$$$$$$$$$$$$$$$$$!!!!!!!!

Dollar to a donut the clanking sound was the crank pulley flopping around. Not sure about the OM617 crankpulley, but later ones can come apart -- I'm fairly certain yours is just unbolted so that the drive belt part isn't attached to the crank anymore.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!