I was working on my TPI Computer today, setting turn on and turn off values for the fan with A/C. As I was waiting to see if I had it right, I guess the High Side pressures got too high ( fan hadn't turned on yet), and the safety valve on the back of the compressor released( spraying R134 and Dye over the passenger valve covers).

I hooked up my guages, and still had 220 on the high side, and 35 on the low side. Clutch was engaged, so the Low Pressure Switch was allowing it to engage, so I assumed that I still had some R134. Ambient was 100. Looked like the pressure was holding, so I tried adding a can of R134. High side pressures crept up to 250, but low side stayed right around 35. Turned everything off, to see if I had a continuing leak. Pressures have held for the last hour.

My question- When a safety valve blows, does it re-set itself? Compressor is a new Delco R4 ( Not rebuilt), only 1 month on the vehicle. Will I be OK to continue adding R134 to get the low side pressures down so that compressor will cycle?

The relief valve should reset, but sometimes they dont. If you can't see or hear a leak you should be ok.

Adding refrigerant will not bring your Low Side pressure down!! The compressor will not cycle at 100 degrees!
250 High/35 Low @100 ambient is about right. Don't add any more refrigerant.

Thanks for the quick response. Checked the pressures once again while the car was sitting, engine off, and they held for 2 hrs, so I don't think I have a continuing leak. Buttoned everything up, and took it for a test drive. Was getting 38-40 degrees at the vent, with ambient at 99, so I can't complain.

Getting a little vibration at idle that I didn't have with the old system- don't know if it's still overfilled, or just new enough that the compressor is still "breaking in". Checked all the bolts, serp belt, etc- everything looks OK. Might try bumping the AC-on idle up a little bit. Maybe it's just found a resonant frequency.