Weird problem, 750IL v-belt for alternator and power steering pump too tight

[GreenSofa89]

I recently went through and replace the v-belts on my 750IL and started having a weird problem afterwards. The power steering and alternator belt started squealing. So I thought I had a bad part and replaced the belt. I used both Contitech, and BMW. It turns out the belt is so tight on it's on, that the idler pulley arm is rubbing on the alternator housing causing a squeal. Once the car is running I can use a flat head and push the idler off the housing and it will stay off while I'm driving, but as soon as I restart the engine it starts back squealing. I checked the part number on realoem.com and it's the right belt, and the belt I bought from the dealership is the right one, but the belt is still too tight on it's own and keeps the tensioner from being in the right position no matter what I do. Has anyone ever had this problem or any idea of what to do?

[CPHES]

No, but were the tensioners taken off at all? Are they put on correctly? Pics would help

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Also, are you sure you have the routjng correct?

[tjpike]

Also, there were two belts lengths available. Make sure you have the right length for your car. When the 750 was given a facelift, they changed the belt size by 5mm i think due to a slight change in alternator pulley size. I ended up buying the wrong belt size which was too big and lead to the squealing issue, replaced it with the right part number and all was well.

[GreenSofa89]

The first time I changed the belt I did not remove the idler puller or tensioner, the second time I replaced the idler pulley and tensioner. But ever since I replaced the belt, the idler pulley has been rubbing on the alternator housing. I'm guessing I got the belt that's too short based on your response tjpike. I'll have to get the longer belt. I didn't realize BMW made two belt lengths, so that helps a lot. Thank you.

[shogun]

here you have the belt sizes for a 2001 750 https://www.autohausaz.com/catalog/c...t_drive_system

[GreenSofa89]

I solved the problem by getting a belt that is an inch and a half larger in diameter. Car runs as quiet and smooth as can be. Thanks for the help guys.