That fan noise is perfectly normal for clutch fan vehicles. The fan kicks on when the temp reaches (X) and disengages when it's cool enough. Your Humvee has the same fan if you tilt the hood and look. Mine crapped out while training at Fort Dix, NJ in the winter and I almost froze to death because the fan wouldn't disengage. Here's in Florida, the fan runs when needed, that's a lot, but you don't notice it when driving. The only cure would be to install an electric fan but you'd still hear it when it was called for by engine heat. Until you can think of a better way to disapate engine heat than a fan and radiator then you're stuck with it the way it is.
BTW...You ought to hear the one in my fire truck if you think the HUMMER's is bad!

 

The fix is to convert to dual electric fans like used on the 2500HD trucks. This will eliminate the noise, and frees up 16hp at the same time. Nelson Performance makes the wiring harness. You will need to add a switch to control manually if off roading and need to go through water. Nelson's wiring harness has connection for a manual switch. You will also either need custom tuning to enable electric fans in ECM to control on-off temps or purchase Diablo Sport Predator Programmer. This programmer also allows you to disable Torque Management which adds very noticable power increase throughout throttle positions and RPM.

 

ARE WE TALKING ABOUT THE BIG TRUCK SOUND LIKE ITS ABOUT TO BLOW UP
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Yep, thats it!

 

i asked my self the same dam question i though my truck was fUp wait is my truck fUp or not cause that sound makes the truck look like a piece of Sht not cool i know is not a truck for speed ...

 

A failed fan clutch will cause overheating when in traffic as the clutch does not engage to draw air across the radiator. When the engine is at operating temp, you can use a rolled newspaper technique to see if the clutch is engaged.

 

THE ENGINE ROAR. It's annoying! ! 2005 Hummer H2 SUT.
My buddy has the same truck and his is quite. What's the deal on mine? I just replaced it. It seems louder than before. I have heard of possible bad fan clutch from the stores shelf life. I bought it from Oriellys.
Any suggestions? Thank you.

 

Maybe his is not working correctly. If it's working you should hear it when it's designed to engage and cool the motor.

 

Thanks. But is it supposed to be on even if engine is not overheating? I get in truck and give it a lil gas and it is roaring. I have to rev it up for it to "break loose".
It is the whole time until I go over 30 mph. It seems strange to be that loud when I ain't even revving it up. The Ford next to me thinking that I am trying to race...lol
But loud to whole time in the super market parking lot is kind of embarrassing. Lol.
Thanks for replying.

 

I have same thing in my trucks but I realize it mostly happens if I start the trucks and don't warm them up. When I just start them and take off, very little power and very loud fan noise. I warm up both trucks for 10 minutes before I go on my way and no fan noise. After driving awhile and making a few stops along the way I will get the fan noise once in awhile but not so often that I need to swap it out.