After doing a partial fill with a R134a, some PAG oil and U/V dye, it looks like there is a slow leak towards the A/C compressor pulley/clutch unit.

The compressor is about 4-years old, and was purchased new from Mercedes, and does NOT make any noise.

Should I add some "A/C stop leak" that supposedly can swell O-rings, or does that cause more problems down the road ?

If so, what brand/pn# do you recommend ?

Is it worth rebuilding ? Will I need special tools ?
If so, where's the best place to get parts ?

FWIW, it a Nippondenso 6CA17C compressor.

:-( neil