I had a weird thing happen on my '83 240D that I am restoring to road-worthiness.

I had been able to start the car with no problems (I was debugging the door locks) and all was well. However, once, when I went to start it (after having started it 30 minutes prior), it would barely turn over. A charger placed on the battery showed a huge current draw on the charger meter.

I wanted to get a new battery anyway, so I got a nice new 1000CCA AGM battery and when I connected the plus terminal, I noticed an arc- like the headlights were on or something (they were not). I didn't leave it hooked up.

After messing with it today, it is acting normal.

Anyway, I think that maybe the glow plug relay was staying on. How common is this? It is the original relay, and the car sat unused in a barn for 15 years. I've been messing with this car for 9 months and not seen the relay fail. Can I take the relay apart and clean/lube?