A few of the car CD players I have looked at have had a loading problem, they used a long silicon rubber roller to get the CD in and out through the slot. The roller had become unbonded from the steel shaft it was on. If the shaft was SPLINED before the silicon rubber roller was moulded or bonded to it, and the bond had failed, maybe the spline was chewing rubber from the roller. The ones I have worked on had a plain (smooth) shaft, and I was unable to glue the roller to the shaft (nothing much sticks to silicon rubber) so maybe the next generation of players have improved the sticktion between roller and shaft by adding a spline. Of course none of this applies to slotless designs. With the player design that has a LID, If the CD is scraping the plastic cabinet either above or below the disc, the scrapings could be in the form of white powdered plastic. It is common with the cheaper designs for the turntable to be gradually pushed down the motor shaft, by the action of clipping the disc onto the turntable, until the CD scrapes the plastic below it. The turntable can be slid back up the shaft to the correct position, which may need to be determined by trial and error. If it is too far out of place, the laser will not focus on the disc and the data will be incorrectly read. More expensive designs use a better turntable, sometimes with a grubscrew to the shaft. On some of the turntables that slide down the shaft, I have fitted a metal sleeve over the boss below the turntable (which sometimes has split) which made the TT firmer on the motor shaft and solved the problem. Of course unless you are lucky to find a metal sleeve of suitable diameter, you will need a lathe to make one.
