rear window issue / oil change question

[1991 300SE Owner]

My drivers side rear window isn't going up and down. Apparently there is a plastic piece or something in there that is broken. I took it into Mr. MB Motors about 2 years ago and they did a fix on whatever the piece is. Enrique told me it was broken and that it was like a $250. part, so in order to save me money, he fixed it so it would at least work. Anyway........I don't live in Los Angeles anymore, so I can't go back to him. I'm up in Sacramento now.

Have you guys ever run into this problem with the window, and if so, can you give me some advice on fixing it? My roomate wants to give it a try, but before I let him I want to see what you guys have to say about this type of repair. It is for my 1991 300 SE Thanks.


Also - I'm learning how to change my own oil. My roomate is showing me how. Can I put a Synthetic Blend in there? He says I should be able to, but I want to be sure..... I know I have to use the MB Coolant only.