Checking Refrigerant Charge

Inspect the refrigerant charge of R-12 by starting the engine and turning the air conditioner on to MAX A/C. With the compressor running (clutch cycled on) view the sight glass (located in-line near the condenser in the engine compartment). There should be few or no bubbles visible in the glass. A constant foaming indicates that the system charge is low. Streaks on the interior of the glass may indicate that the system is totally discharged.