2001 suburban alternater chirping
 

I just replaced the serpentine belt, belt tensioner, and idler pulley on my 2001 Suburban with the 5.3 engine. Now a loud chirping sound is coming from the alternator. What gives? Any fixes?

A neighbor gave the belt a spray of belt conditioner and the chirping went away. I celebrated for 3 seconds when a new noise started up. Now it's a knocking or slapping sound which seems to be coming from the left side of the engine as you are facing the front of the truck. It's loud at first, but very gradually goes away after about 6 or 7 minutes. But come the next morning the loud noise comes back again. I did the old trick of putting an ear to a long screwdriver while touching as many parts as possible including the AC compressor, the new tensioners, the new idler pulley, the alternator, the water pump, and the power steering pump but heard nothing. Looks like I'm going to my mechanic next, but any ideas?

I had a similar problem several years ago. turned out I was sold the wrong serpentine belt. It was a bit too long. when I put the correct one on, the noises went away for good.

I bought the belt at NAPA. I went to their online site and confirmed that the belt that they sold me is the right one. Also, the arrow on the tensioner is within the two lines so the belt is the right length. I'm just hoping that it isn't something internal that just happened to pop up at the same time I fixed the chirping noise. That would be quite a coincidence tho. Thanks for the suggestion.

if the noise went away briefly after your neighbour sprayed the belt...its a belt noise. Get a belt from the dealer. Things I don't buy aftermarket are air filters and serpentine belts.

The noise I've been hearing seemed to follow the belt so I removed it and sure enough there is a flaw on the back of the belt. I didn't check it before I installed it, so I can't be sure that it came that way. But I did find out that it is a low end Gates belt. I'm returning it and paying the extra $11 for Gates' premium belt. Don't mean to keep anyone on the edge of their seats, but I will post the results later.

Check all you pulleys carefully for defects that could damage a belt

The cheaper belt that I put on had a flaw on the smooth side of it. I upgraded to a premium Gates made belt and it is as quiet as can be. Lesson learned...again.

The new belt was flawed, so I replaced it with a better Gates belt and all is quiet. But I did also check pulleys and found that the power steering pulley had a about a 1/16 inch play in it, pulling it in and out. I don't know if there is any tolerance for that, but it looks to be my next project I guess.

check a new pump before you pull any parts...I did the same thing on my old Taurus only to find the new pump has the same play.