We have published our supported environmental tolerances on the web site (Tech page). These are essentially the stated tolerances of the hard drives.

In practice we are aware that car players are being used in far harsher conditions (both hot and cold) and we haven't yet heard of a disk (or any other) failure as a result. It seems that the product is very tolerant of such conditions, but we must advise that it is only used within the limits that we have stated.

If we were to ever get a warranty issue involving a fried disk, and the drive manufacturer post mortem indicated usage outside of tolerated environmental limits, we would certainly consider charging for the replacement part. Those post mortem tests are remarkably accurate.

Rob