Baked

I just picked up a C63 AMG 507 edition last November and drove it straight into the garage for the winter. Can't wait to get the streets cleaned and get it out this spring to get the break in period over with.

I do have a question someone might be able to help me with though. I have found this line under the car and cannot figure out what this might be. It's obviously not an oil, antifreeze, etc. but it leaked from some where under the engine bay. It's almost like a hard water calcuim type of powder. I cleaned the floor and started the car mid winter, the next day the line was back. No clue what it is and haven't been able to get under to take a look yet. Just wondering if anyone would know off hand?