It's only been about a year sence I converted my 89 300e from R12 to R134. My compressor went out about a yea ago and when I bought a new one it was for 134, so I replaced reciever dryer and the expansion valve and recharged the system with 134.
It dosn't work well in stop and go traffic but it works fine up on the highway.
anyway, today my compressor started making noises. when Iturn the A/C on the cutch on the compressor starts to engage, but then it just locks up.
Can anyone tell me what might cause this and if it can be fixed or am I going to buy another compressor again after only about 14 months.

Don't sound good. If you do need a compressor you need a proper flush and re-oiling no matter what refrigerant you use. While I would never convert an early 300e, the compressor should do better than 14months if the thing was oiled properly. The compressors on early (-89) 300Es are too small to do well even without the conversion. I'd put it back R12.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

If it were heavily overcharged it might cause this. What are the pressures? Most likely the compressor is gone. If so, don't even THINK about putting in a new compressor without a thorough flush as Steve suggests. When a compressor fails internally much debris is strewn through the system and if not removed the new compressors life can very well be measured with a stopwatch.

Good luck,