there can be a couple items pertaining to the AC, 1 which could be too much oil would cause a squeeling because of hydrolock, thats when there is too much oil, the other could be a tired belt. The belt might look good as in no cracks etc but if it drys out it can slip even tho lookin good. If you scrape it with a finger nail on the grooved side it should feel rubbery if not its time to change everything, waterpump, thermostat and housing, antifreeze etc. start with the bacics and go from there.
95 E34 530I V2.37
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Those who make peaceful revolution impossible will make violent revolution inevitable.
John F. Kennedy