My post may not have been very clear: I did not mean bubles when (FIRST) turned on, I meant bubbles when the air conditioner is turned on (and running), as opposed to turned off (not running). At least, this is what my tech told me to look for before I had him fix the slow leak in my r12 system and convert it to r134a.
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E