Never disconnect any part of the air conditioner refrigeration circuit unless the system has been discharged by your Audi dealer or a qualified refrigeration engineer. If the compressor or condenser obstructs other mechanical operations such as engine removal, it is permissible to unbolt their mountings and move them to the limit of their flexible hose deflection, but do not disconnect the hoses. If there is still insufficient room to carry out the required work, the system must be discharged before disconnecting and removing the assemblies. The system will need to be recharged upon completion. Regularly check the condenser for clogging with flies or dirt, and clean the hose with water or compressed air. Additionally, regularly check the tension of the compressor drive belt, which should have a deflection of about 10 mm (0.39 in) at the center point of its longest run. If adjustment is necessary, increase the quantity of spacers between the crankshaft pulley halves to reduce tension or decrease them to increase tension. Access to the pulley is gained by removing the intake grille, and the spacers must be positioned on either side of the inner pulley half as needed.