Hello, I just bought a 1989 190E 2.6 and it didn't come w/ the owner's manual. I want to do an oil change but i don't know how much to put in or what grade to use.

I also have a problem w/ the engine temp. Whenever i'm in traffic my temp gauge slowly rises and then when I get at a constant speed, it goes down. The highest it's gone is like 110C and I don't know if it could have gone higher because I reached my destination and quickly shut the car off (kind of freaked out). On the highway it always stays at a cool 80C. What's going on??