My 2000 GTP compressor is making a ton of noise when both on and off, and I have no cold air. It will stay cool for a week if I put a can of refrigerant in there, and then fade back to hot.

I have a new compressor, accumulator, and orifice tube on the way and need to know if there's anything else I should replace at the same time? The compressor indicates that it comes with the seals and rings. Any other seals or o-rings I might need?

Also with regards to flushing. Since it hasn't locked up, do I need to flush before installing or should I be okay with just doing a flush after all the new components are in place?

Thanks,
Steve