Possible Concerns

WARNING: This page is about a different variant/trim than selected.

NOTE:

The A/C system is functioning correctly when the air flowing from the instrument panel vents has a temperature of 7⁰ C or lower.

Setting on Climatronic "LO".

Setting on A/C system "AC" on; "max" ; "cold".

NOTE:

With all complaints marked with *, refer to PRESSURES, CHECKING .

Total cooling system failure. *
Insufficient cooling performance at all vehicles speeds or engine speeds. *
None or insufficient cooling after driving a few miles. *
A/C compressor, A/C Clutch -N25- or A/C Compressor Regulator Valve -N280- are switched off by A/C Refrigerant Low Pressure Switch -F73-, A/C Refrigerant High Pressure Switch -F118-, A/C Pressure Switch -F129- or by A/C Control Head -E87- or Climatronic Control Module -J255- due to excessive or insufficient pressure. *
None or sharp decrease in fresh-air supply after driving several miles (evaporator iced up). *

From these, the following complaints may also occur:

The A/C compressor makes noises

-- Re-tighten compressor securing bolts and compressor bracket using a torque wrench.

-- Check routing of refrigerant lines; they must not touch other components and must not be subject to strain (align if necessary).

Noise (refrigerant hammer) occurring immediately after switching on air conditioner and/or when cornering or braking:

-- Discharge, evacuate and charge refrigerant circuit (too much refrigerant in circuit).

NOTE:

Too much refrigerant oil in the circuit could also cause this problem. This could occur if the amount of refrigerant oil was not adjusted when replacing the A/C compressor. If this occurs, flush the refrigerant circuit with refrigerant R134a, refer to REFRIGERANT CIRCUIT, FLUSHING (CLEANING) WITH REFRIGERANT R134A .

Drain the refrigerant from the A/C compressor. To facilitate this, the ribbed belt pulley or magnetic clutch plate on the A/C compressor should be rotated by hand. After flushing, the entire quantity of refrigerant oil specified by vehicle-specific Repair Information should be added to the refrigerant circuit (50 grams directly in the A/C compressor).

Water sprays out of vents (in dash panel or footwell) although air conditioning system is otherwise functioning properly:

-- Check proper routing of condensate drain; it must not be crushed or kinked.

-- Check condensation drain valve, it must not be clogged by wax or underbody sealant and must open and close properly.

-- Check plenum chamber cover; it must not be damaged and must be properly installed (to stop water running into evaporator).

-- Check water drains in plenum chamber; they must not be blocked (e.g. by leaves).