I've got a '82 300SD w/ about 250k mi. Had it for a month now. Past owner didn't give it much love. I'm going thru a quart of oil every 150 miles or so and I'm pretty sure that its coming from the valve cover gasket. I tried giving the valve cover bolts a bit of a tighten to help remedy the problem and found that one of the 4 nuts was stripped. The threading on the bolt itself looks dubious as well. Also, regular washers were used as opposed to crush washers. I found another nut that seemed to fit, I tightened it down, but its still leaking. I guess I should try replacing the gasket next. A couple questions:

1. i'm new to foreign cars. Let me restate that. I'm new to most cars in general. Will I be able to find replacement nuts at a hardware store? Do I need to worry about thread pitch or count?

2. should I try to re-thread the bolt or is this an easily replaceable part? Judging by some pictures i've seen on the dieselgiant site, it doesn't look like something I'll be able to replace easily.

3. what torque should I tighten the nuts back down at?

Thanks for the help.