After I got my engine rebuilt, I noticed my preglow indicator coil did not work anymore. There is conductivity between the coil in the car, and the glow plugs. Any thoughts? Does this normally go out?

you have power at the plugs? Are you sure all plugs are hooked up properly with the ground strap from the temp sensor attached to the #1 gp.

If so, it could just be a burned out bulb.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

The plugs work fine and the car starts. The system on the W115 uses a metal coil that glows red once the glow plugs are warm, so it cant be a bulb. I wouldn't know exactly what the "correct" hook ups look like do you know where I can find pictures?

What kind of glow plugs are in the engine now? Are they the upgraded type (usually a single, insulated wire between each plug) or the original (thick, squiggly metal wires between the plugs). If the former, the glow plug indicator element may have been bypassed or simply doesn't work correctly with the new plugs.

Does the alternator warning light dim slightly when you pull the knob to the preglow position? If so, the glow plugs are working properly. If not, you are only getting power to the plugs while you are cranking, which probably either the pull-start switch isn't working right or the dash light element is burned out/cracked.

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1976 240D "Katja"

The engine is using the standard original glow plugs. Conductivity exists between the glow plugs and the indicator element if I remember correctly.

The battery warning light goes out when I pull the car to the preglow position. The car starts and functions fine, I just have to count to approximately 15 seconds before I start it. I'd like to be more accurate and have it functioning as it was.