97 Toyota Avalon: I replaced the timing belt due to a loud clicking/clacking and squealing noise that all but goes away when the car is warm (~15 mins of driving). I took the car to the mechanic and he opened it up and saw that one of the pulleys was bad (tensioner pulley), so I replaced the tensioner pulley, idler pulley and the timing belt, but the waterpump looked fine; no leaking, and the pulley didnt wobble or anything and was just changed 2 years ago and about 30k miles, so I didnt change it. The noise went away for about 2 days, then came back, my mechanic thinks it's the waterpump making the noise now, but is not 100% sure. I wanted to be sure that it is the waterpump making the noise before tearing into it again, so if the waterpump starts to leak soon, I will know it is bad, rather than just guessing. I eliminated the PS pump, alternator and compressor belt/bearing as the cause, as I ran the car with no accessories and it still made that noise.