Squeal and flapping sound

[H2inMD]

2003 H2 95000 miles. put new drive belt and tensioner on. Still need to do the A/C belt and tensioner.

It seems to squeal like a pig as I start out. It might clear up and it might not. Sometimes if I accelerate it start again.

Seems like it neutral it hardly makes a squeal.

Then, if you step on the gas, sometimes it will make a flapping sound, weird. I can't really describe the sound its different. The check engine light will flash. no codes though.

Ideas?

thanks

[BradO]

Had something similar on my 2006 w/ 64k. Dealership replaced both tentioners, fan clutch, and both belts. Solved my issues. I didn't realize there were 2 tentioners, etc until they pointed that out.

[H2inMD]

Its seems to get worse if you push the engine, we were reving it up to try to hear the noise and it got worse.

next step , when its cold, I am going to take the belt off and see if it still makes the squeal. This will start to isolate the problem.

any other ideas?

[H2 Bill]

On the "main drive belt" there is a tensioner pulley and an idler pulley. I had to change both to make the noise go away.

[H2inMD]

we've diagnosed it better, so I started a new post. Whistle from Intake manifold?

[H2inMD]

Unbelievable. 3 nuts/bolts broke off on the exhaust manifold passenger side.

You got your tick tick sound, then as you accelerate, it whistles(cat screech) with more exhaust flow, then if you get on it, the manifold itself is lifting on and off the head hence the flapping/banging sound.

Saw the tech bulletin on the fasteners, why didn't the original dealer ever contact me, why not GM. The tech bulletin says to replace if brought in for manifold service. Guess if it fails you bring it in. Would have been nice to change them before the failure.

[pdsq99f4]

Originally Posted by H2inMD

Saw the tech bulletin on the fasteners, why didn't the original dealer ever contact me, why not GM. The tech bulletin says to replace if brought in for manifold service. Guess if it fails you bring it in. Would have been nice to change them before the failure.

If you were GM would you send letters to everyone who owns a Hummer saying "you may have some exhaust manifold bolts break, so watch out"? Do you know how much that would cost? It would definitely bring me more business though as a technician. I'm sure if you got your vehicle serviced by someone who KNOWS your H2 they would have seen the broken bolts a long time ago. I know I would have.