Passat Sedan V6-2792cc 2.8L DOHC (AAA) SFI (1997)
Sight Glass: Description and Operation
With a properly charged A/C system and A/C clutch engaged, the sight glass (arrow, if equipped) should remain clear and bubble-free.
NOTE: The mixture of R-134a refrigerant and refrigerant oil (PAG oil) may appear milky in the sight glass.