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Old 02-18-2013, 04:29 AM
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diggyd357 diggyd357 is offline
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Location: Louisiana
Join Date: Sep 2012
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Mein Auto: 97 528I
Originally Posted by BigBoy740il View Post
Here are a few things to check.
1. Turn on AC system and ensure that the compressor clutch and electric fan are spinning.
2. System operating lowside pressure should be around 30-32 psi. If the pressure is low, have the system professionally drained. BMW system must be evacuated, new compressor oil added and freon added to a specific weight.
3. If the compressor constantly cuts on and off, I would check for high system pressure, a bad sensor, or bad expansion valve. The AC tech will have the manifold guages to check the high and low side pressures.
Once you have the system functioning properly, a good practice is to run the AC system 5-10 minutes per month. This allows the system to cycle the freon and lubricate the seals.
Not to hijack the thread, but I have a question.... Why must you evacuate the system simply from a low.charge ? I can understand evac if there is no charge or car has been sitting, but topping off refrigerant due to a low charge seems like a harmless solution. Is there something specific to BMW AC systems that I should know about ? Thanks !

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