What size belt what I need to bypass The AC pulley for a 2007 Ford Taurus

That's not the way you do it, you remove the AC Compressor and fit a Bypass Pulley in its place. The belt and routing remain the same.

https://www.google.com/search?q=2008+ford+taurus+ac+bypass+pulley

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No, because the routing doesn't work out right.

https://www.2carpros.com/diagrams/ford/taurus/2002

So they sell Bypass pulleys and you just use the same belt.

https://www.google.com/search?q=2002+ford+taurus+3.0+l+AC+compressor+bypass

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Cut the belt and measure the length it will take to go around all but compressor pulleys then go to auto parts store and ask for a belt of that length.

belt 82 1/2 " long at parts store --part #5060825 -- fits perfectly to bypass AC on 2003 Taurus
you will need to purchase a serpentine belt for a taurus that isn't equipped with airconditioning, and that will match up just right with the other pulleys

it will be pretty much hit and miss to get the right bely
you can get an estimate of the belt length by measuring the distance between where the existing belt contacts the power steering and crank pulley
make a note of that length (A)
now using a tape measure measure from the contact point on the crank pulley around the ac pulley to the contact point on the power steering pulley
make a note of that length (B)
now take A from B and reduce the original belt length by that amount
example -- if the original belt is 1485 mm long and the difference is 145 mm then you would be looking at a new belt length of 1340 mm
well that is the general idea
personally replacing the ac compressor is a far better idea , even if you do not re-gas the system or replacing the ac pulley bearing --cheaper still

If you are going to bypass it then you need a different sized belt or a different pulley and believe me that's guess work till you find the right one

auto zone sells a bypass pulley Pn 34166 Think it uses the same belt

2004 ford taurus belt size to bypass ac compresser is 68inche belt i spent 7 hours testing 5 differnt belts 82 inchs is standard belt not a bypass belt 680k is the belt not a perfect fit you need to buy a smaller idler pulley smooth no groves then you have perfct fit i just wnt through this today all day

Oreilly`s sells an AC replacement pulley for $45 and use the same size factory belt. I would go this route.

simple trick provided you can do this by running some twine around your pulleys allowing for1-2 inches less for slack adjuster an that will pretty close.or they may have for that system without ac meaning the condenser unit.