I need help! My 2008 Chevy Express has a loud chirping or grinding noise at idle and ONLY when it gets warm past 150F in the morning. First start every morning zero noise but as soon as engine warms up the noise starts. You can tell is a tick-tick-tick when revving the engine but it pretty much goes away or is much less noticeable while driving on the street, and completely unnoticeable on the highway. As soon as you let go of the gas or get to the light the noise comes right back.
It is driving me crazy and my right ear actually hurts from this when I'm making deliveries.
Van has full synthetic 5w-30 oil and engine barely dirties the oil in the interval. I have replaced both belts, water pump, clutch fan and harmonic balancer to no avail. I have also ran the engine without belts (after all the work was done, now I realize I should have done it first) and the noise is still there so it is nothing on the pulleys.
Using a stethoscope does not help because you can hear the noise everywhere. It kind of sounds like it's coming from the torque converter or the exhaust? Maybe some internal engine components who knows.
Van has 263000 miles but was always well maintained and I am almost sure the engine and transmission are new since they are so clean. I bought this van a year ago from an auction and van was used by Budweiser to deliver beverages.
Video attached!
Any suggestions are much appreciated.

Thank you

 

sounds like a worn out belt pulley , water pump, or alternator

 

No but thanks. Re read post please. Thanks for reply though.

 

I did read it. I'm just telling you what I think it sounds like. It's too slow to be anything else.

 

Sometimes no matter how right we are, we are perceived wrong,lol.

What might help is if we offered some explanation,,,maybe !

I believe what our moderator was trying to get across was,, if there is a bad bearing involving one of the pulleys, it binds and causes the belt to slip producing the chirp sound.
Easy proof, just take the belt off and spin each pulley and most times you can feel the grinding inside.

Wanna try it ??

 

I had some sounds that might be what you are having. Turned out to be a failed roller lifters. Not easy to check on them 6.0's. Have to pull the head to remove the lifters. If you remove tge intake and Valley cover. You might be able to see the cam surface. Do you have DOD or AFT. Maybe something in those systems is failing.

 

Vans don't have cylinder deactivation.

 

Thanks but I did run the engine without both belts and the noise was still there. I wrote that above. That’s when I decided to change the harmonic balancer but that didn’t fix it.

 

Ok, still would need to investigate for failing roller lifters.