Loud Chirping Noise
 

My 2002 3.0 Ranger has a loud chirping noise (not a squeeling noise) when running cold. Gradually the sound will get less pronounced and less high pitched as the engine warms up.

I sprayed some water on the top of the serpentine belt and the sound went away momentarily. I think that eliminates the Camshaft Sensor as the cause of the chriping noise.

So does this mean just the belt needs to be replaced - or could the tensioner and/or idler pulleys also be the cause of the chirping noise?

Either the belt or a pulley..

Take the belt off and start the engine. If the chirp is gone you know its a belt and/or pulley. While the belt is off check out all the pulleys. See if any are loose or seem to have bad bearings. Depending on how many miles are on the truck I'd replace the tensioner and idler pulley. They're fairly cheap and its good insurance.

Sounds like it could be a belt or pulley. My Ranger has the same issue. Going to put a new belt, and idler pulley on it this spring. The motorcraft pulley from your dealer is a "improved" design, and comes with the install bolt. Might be more money than the aftermarket, but worth it. IMO.

Check the cam synchro ASAP my went bad at 55k miles and as I understand this can cause engine failure

Theres a big difference between a chirp and a belt squeak....if it went away when u sprayed the belt..then its the belt or pulley.

That would be the "chirp of death" caused by the cam syncro. Very common on the 3.0.

I would replace that ASAP. If you dont, you will lose oil pressure and seize your engine.