This will be my california 300d's first real winter, and I have a few questions.

1) Were these cars factory rust-proofed? I have waxed the body a couple of times to build up layers of wax, but I'm also concerned with the under-carriage.

2) Having never used a block heater, how long should I leave her plugged in if parking outside. I hope the answer is all night long, because I wouldn't feel like waking up in the early hours to plug her in.

3)What weight of oil should I use? Keep in mind I commute to Rochester 15 times a month for a total of about 2500 highway miles a month. Also, economicaly speaking, it would be awfuly rich for me to switch to synthetic for I change the oil every 3000 miles or about every month and a half. I currently use 15-40, and the car consumes a quart every 2500 miles.

Thanks for reading this long winded post, but I kind of want to get an idea what I'm in store for this winter. Al

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2012 550CLS
1982 380SL
1985 300D
1998 ML-320
1997 E-320
1984 380SE