[HotZ28]

In order to get a warranty on a compressor, you need to install a new accumulator-drier and an expansion valve. (Not condenser). When you remove the expansion valve, you will notice a screen on it that traps small particles. If it is clogged, you have internal contamination and need to do a complete system flush prior to installing the new compressor. If you do not, it will not last long!
You can also tell if the pulley bearing is bad, just by turning it with the belt off. If the problem is external instead of internal, you will not have an excessive amount of internal contamination, however, it is still a good idea to flush, prior to installing high dollar parts.