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| For all problems marked *, refer to → Chapter„Checking pressures“. |
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| If problems are only encountered at one evaporator on vehicles fitted with two evaporators, also check the pressures in the refrigerant circuit. |
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| Total cooling system failure.* |
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| Insufficient cooling output at all vehicle or engine speeds.* |
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| No or insufficient cooling after driving a few miles. * |
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| No or insufficient cooling at one or via both evaporators (on vehicles with two air conditioning units). * |
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| Air conditioner compressor, air conditioning system magnetic clutch -N25- or air conditioner compressor regulating valve -N280- shut off by a pressure switch (e.g. -F73-, -F118-, -F129- -F129- or by the operating and display unit for Climatronic air conditioning system -E87- or the Climatronic control unit -J255-) on account of excessive or inadequate pressure. * |
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| No or sharp decrease in fresh-air supply after driving several miles (evaporator iced up). * |
| In addition, the following problems may occur: |
| Air conditioner compressor noise |
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| Re-tighten the bolts for the air conditioner compressor and the compressor holder using a torque wrench. |
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| Check the routing of the 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 the air conditioner and/or when cornering or braking |
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| Discharge, evacuate and re-charge the refrigerant circuit (too much refrigerant in circuit). |
Note | Too much refrigerant oil in the circuit may also result in this problem (no adjustment of refrigerant oil quantity, for example, on renewing compressor). |
| Water sprays out of the vents (in the dash panel or footwell) although the air conditioning system is otherwise functioning properly |
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| Check proper routing of the condensation drain; it must not be crushed or kinked. |
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| Check the condensation drain valve; it must not be gummed up with wax or underseal and must close properly. |
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| Check the plenum chamber cover; it must not be damaged and must be properly installed (to stop water running into the evaporator). |
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| Check the plenum chamber water drains; they must not be blocked (e.g. by leaves). |
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