I recently purchased a 1993 J30 with 130xxx miles. What is the best suited, all around oil weight for this engine? I've read either 10w30 or 5w30. I would rather stay away from synthetics & change oil every 3,000 - 4,000 mi. Old school maybe? I live in Missouri where temps. fluctuate greatly with the seasons. I have also encountered driver side window issues. The window will go down, but will roll up only with assistance?The bose radio will not play Cd's. The radio displays error when a cd is inserted?Any advice would be greatly appreciated.Overall, the car is a joy to drive, if I can get a few of these issues resolved.

Regarding the window, I had a similar problem (slow up) but when I was swapping out the speaker I noticed the rubber track at each side of the window (inside the door cavity) was dry. I added Rustcheck (a Canadian product which claims to lubricate all sorts of rubber on cars in addition to being a supurb anti-rust solution) and wiped off the residue. I also lightly lubricated the cable that attaches to the pully that raises/lowers the glass. It seemed to free up the window and now raises quicker but not as fast as the passenger side. It could be a sluggish motor since it's used more than the other door window motors.