Volkswagen Polo Service & Repair Manual: Checking

Volkswagen Polo Service & Repair Manual / Refrrigerant R134a Servicing / Pressures, Checking / Checking with Expansion Valve and Receiver/Dryer, without Regulated A/C Compressor / Checking

–	Turn off the ignition.

–	Connect pressure gauge battery (A/C service station).

–	Take pressure gauge readings. There are two possible results A and B.

Ambient Temperature in °C (°F)	Pressure in Refrigerant Circuit in Bar (psi) Positive Pressure
15 (60)	3.9 (57)
20 (68)	4.7 (68)
30 (86)	6.7 (97)
40 (104)	9.1 (132)

A- The pressure in the refrigerant circuit is lower than the pressure specified in the table. There is not enough refrigerant in the circuit.

- Search for leak with leak detection device.

- The pressure release valve is open, check coolant fan activation according to the wiring diagram.

Check refrigerant pipes and hoses to see if they are bent too sharply (cross-section constrictions) or have external damage. If no malfunction is found, flush refrigerant circuit.

B - The pressure in the refrigerant circuit matches the table or is higher.

–	Start the engine.

–	Set A/C system to maximum cooling output.

–	Open doors.

–	Open vents in instrument panel.

The A/C compressor is driven by the engine via the magnetic clutch using the ribbed belt.

Note

If the A/C compressor is not driven, check A/C Clutch -N25- voltage supply.

If the voltage supply is OK, repair the magnetic clutch.

If the A/C compressor is driven, check refrigerant circuit:

–	Bring engine speed up to 2000 RPM.

–	Observe manometer battery:

Specified Values

High-pressure side:

Increasing from pressure with engine not running to a maximum of 20 bar (290 psi).

Low-pressure side:

Decreasing from pressure with engine not running down to 1.3 bar (18.9 psi).

Test Requirements

Radiator and condenser are clean (clean if necessary). The ribbed belt for the A/C compressor and alternator tensioned correctly. ...

Checking with Restrictor, Reservoir and A/C Compressor Regulator Valve -N280-, Externally Regulated A/C Compressor

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