Originally Posted by Zacm90gt
Okay I was wondering if the air pump in the 1990 mustang was still necessary (the pump that sits below the alternator bottom left pulley under the hood) me and my dad read online and it said it wasn't and if your having problems just to get a serpentine belt for the mustangs without a/c and just bypass the pulley but I wanted another opinion on the subject
It is only necessary if you need it to pass a smog check.
You can either run a shorter belt to bypass it or use a smog pump delete kit.
Be sure to keep your water pump and other accessories turning in the correct direction if you use a shorter belt.