A/C System - Capacity/Charge Check/Torque Specifications

REF. NO. MBNA 83/40

TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: February 1992

SUBJECT:
MODEL 140
A. AIR CONDITIONING SYSTEM CAPACITY
B. QUICK CHARGE CHECK
C. TORQUE SPECIFICATIONS





A. R134a (non-CFC) Refrigerant capacity

B. Quick charge check





1. Clean sight glass on receiver/drier. Additional access can be gained by removing left side headlamp bulb access cover.








2. Disconnect connector from coolant temperature sensor B10/8 and bridge connector terminals with jumper wire.

3. With engine idling, switch on automatic climate control (DEF).





4. Observe sight glass through opening in radiator support (arrow) and simultaneously remove jumper wire from connector.

Refrigerant should rise soon after the compressor clutch engages. The flow should be free of bubbles or foam (refrigerant is clear).

Note:
An accurate check of the charge is not always possible using the sight glass. At higher ambient temperatures (greater than 35°C) some bubbles may be visible even with correct fill quantity.

When there is a loss of refrigerant or system leaks are suspected, the correct charge can only be ensured by completely evacuating (recycling) and refilling system. System should first be checked for leaks. The correct charge can only be established by weighing the refrigerant or by using a recharging cylinder or automatic air conditioning recharging station.








C. A/C system connections/torque specifications (Optional rear A/C shown).