Air Conditioning problem
1998 BMW 535 V8 Two Wheel Drive Automatic 130000 miles
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hi, i need to re-gas the system. the system seams to engage once the air con is switched on (noticeable as engine revs increase)but a check with a pressure gauge from a car parts dealer who is not an air con engineer shws the system in the red when he believes the reading should be in the green. he did not proceed.can you help.

was the high side pressure in the red? if the engine cooling fans dont come on when the ac is on it will cause the high side pressure to go through the roof becasue it relies on the fan to cool the ac condenser. check that first

The high and low pressures, ambient temp and humidity all are factors in determining any air condition issue. When reposting please send these data.