Hello, I have a 2007 550i. Can anyone tell me if I need the compressor belt tool to install the A/C belt or does this car have an A/C tensioner. I would appreciate it if someone can direct me to a DIY on how to change the A/C belt for a 550i, I have searched this site and all i found was for a 545i. Thank you for any help extended.

 

You release tension on the water pump/alt/power steering-ARS pump belt and remove it. IF you are replacing the belt then cut it to remove.
Get a 27mm socket for crank bolt head and a breaker bar, or even better a long handled 1/2 drive ratchet, and place that on crank bolt. Put belt on crank pulley and start it on the bottom of a/c compressor pulley and hold it while turning the crank clockwise. Be sure ignition is not on so engine will not have any possibility of starting or kicking backwards. The belt is a "stretch" belt and uses no tensioner.
You may have to rotate crank a few times and ease belt back into the grooves if it is not already there after it has gone onto pulley.

This best done from below with the forward pan under engine removed.

 

Thank's for the tip, I will not need the tool then?

 

I have not used the tool. Regardless, you have to turn the engine over by hand and I had no trouble holding the belt onto compressor pulley while turning the crank.

 

Thank you much, I will try to do this this weekend.

 

Abe76247 thanks for the tips and the heads up on the tools needed, I was able to successfully change my Fan and serpentine belts, though the fan belt was a PITA to re-install.
I was hoping to fix the problem which is a whirring sound under the hood when my car drives over 10 miles and only sounds off upon deceleration and when stopped, the noise does not come out during cruising speed above 40 mph. Help anyone? Thank you.

 

With it running and making the noise remove the dipstick at rear of engine. IF the noise stops then it is likely one or both of the CCV devices.

 

I will try that, thanks

 

It is indeed the CCV, one of them is torn, I think this will solve my issue once replaced. Thanks again abe76247