1700 miles on new timing belt. Have been getting a weird noise almost like a rattle once car is warmed up lately. Took timing covers off and while running I could see the belt moving a little side to side on water pump pulley and in sync with the noise.

Upon further inspection it seems like the belt is loose between the cams going around water pump. Car does run fine and never heats up past center on gage. Here are some of what looks like the blue side of belt is wearing down to the black underneath from maybe slipping some on it some. I can get my hands down there and manually turn the pump pulley. I think I am safe in assuming it's too loose. Other side of cams both ways belt is definitely much tighter. Would not pre tensioning the new tensioner cause this. I ask because it could be a possibility.

When I was reassembling everything I got to the point where I was installing fan clutch and noticed I had left the plates that cover the end of the heads off. It was almost midnight and very tired. I tore it all back down and put back together to the fan clutch step in about an hour and went to bed.

Now I did have pulleys loose and all other steps were done exactly as per instructions. If I did not tension properly would it be just ripping all back apart. Popping cams loose, using cam and crankshaft locking tool at TDC and compressing tensioner and retensioning?

 

Even if I had not pre tensioned the belt correctly (not completely certain I didn't) would the tensioner eventually take care of that? Could I have got a bad tensioner right out of the box? May start to rip into this today. Trying to get some thoughts before I do.

 

I must have pre tensioned properly. Went out to start tearing into it and checked belt. It's tight. Must be why I hear noise only after warm. Possible for a new tensioner to fail in a way that when warm it loosens up?

 

You may get times in the rotation where it is looser than others, but it should never be loose. The only way to install the belt properly is to have the crank and cams lined up right, then wrap the timing belt around the crank sprocket first, and work counter-clockwise, making sure the belt is pulled as tightly as possible between each pulley/sprocket, finishing by wrapping it over the tensioner roller. Pull the pin on the hydraulic tensioner and it'll put tension on the whole thing. Long as you have it as tight as possible on each run between pulleys, it'll be right.

 

I wish I saw your post before installing the new tensioner. That way makes sense. I did get it all the same tension between all the rollers and cams. Rotated engine twice by hand and all was still tensioned the same.

Noise is still F'n there. Took car for a 5 mile round trip last night to store. Got home and pulled right timing cover and belt was snug as before. After dinner two hours later I came out and it was loose again. Real loose. Bout 3/4 an inch deflection either way for about 1.5in total. You could wiggle the belt. No clue what's going on here. All the rollers and water pump pulley seem fine. Here is a video I made last night of the noise it makes when it slides along water pump pulley. It's the quieter of the noises. I know I have a high pitched whine I need to take care of. Thinking alternator bearing or PS pump.