The blower motor bearings are starting to fail. Mine whines at start up now and then. If you have a mechanical clutch, replace it if it's old. It will help with A/C cooling. Low pressure can be good, however high pressure is important too. At 100F, low pressure should be higher. It should be in the (45 is acceptable) 50-55 PSI range. 275-315 PSI on high side. My 3.0 has a brushless auxiliary and mechanical fan. Once the engine is to temp, it can maintain 42F in dead slow traffic and stop signs.

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'06 X5 3.0i - bought @143,123 miles (12/26/20)