Updated Idler Pulley and FEAD Belt Installation
The 4.3L V8 Vantage can often develop a "chirp" that is present when the engine is cold. The problem was fixed on the 4.7L V8 Vantage by changing the idler assembly pulley and FEAD belt. The parts for the 4.7L V8 are a retrofit for the 4.3L V8 and eliminate the chirping sound from that engine.
To fix the chirping problem you must install both the updated idler assembly (the pulley) and the updated FEAD belt. If you swap out the pulley but continue to use the old belt, you will still get the chirping noise!
DISCLAIMER: As always, follow all safety protocols. Don't undertake this task if you aren't comfortable with it and fully understand it. You are ultimately responsible for anything you do. Neither Redpants, LLC or myself is responsible or liable for anything that may occur.
Make sure the engine bay is completely cool before starting this job - you don't want to burn yourself!
Get the car up on jackstands, or use a lift.
Get under the car and use the 8mm socket and ratchet to remove the metal bracket holding the return line for the air-oil separator.
Remove the original FEAD belt (I typically cut it and then pull it out).
Use the 15mm socket and ratchet to remove the idler assembly (pulley), then install the new one in its place.
Route the new FEAD belt around the maze of pulleys, ensuring that it's properly seated on each pulley (especially those that make contact with the ribs on the inside of the belt!). You won't be able to fully seat the belt in place just yet, it'll be too short. The best way I've found to do this is to get the belt seated on every pulley except the A/C compressor.
Use the 3/8"-drive pry bar to pull the tension arm. This will give you more slack in the FEAD belt and allow you to work the belt onto the last pulley. Once the belt is seated, you can carefully release the tension arm.
Check the routing of the entire FEAD belt and ensure it isn't twisted, misaligned, or otherwise not routed correctly. If it's good, reinstall the air-oil separator bracket with the 8mm bolts.
Bring the car back down off the jackstands or lift, make sure everything is reconnected, the belt is oriented as it should be, and then start up the car. The 'chirp' should be gone.