I have an 07 Colorado with a 2.9L
The fan runs super loud whenever I accelerate and increases as my RPMs increase. It does NOT overheat and seems to drive fine otherwise. So far I’ve replaced the fan clutch and the coolant temp sensor but no dice… it’s not throwing any error codes. I don’t mind having to replace things since I just got a great deal for it from my boss and know that it needs some love, but I’d really like to be able to pin point the problem without having to waste time and money replacing 15 things that don’t need replaced. Any advice would be greatly appreciated.

I'm going to guess it's a bearing in the idler or the tensioner. Nowadays you can buy a kit that includes them and the belt.
Those bearing usually last about 75k miles or so.

 

I'm not as familiar with the 355 platform as the 360s, but do you have a normal thermal fan clutch or the electronic plug in type.

 

I was thinking the same thing, also being far more familiar with the 360 platform than the 355, but I think GM stopped using the electroviscous fan clutch in both platforms in 2006 (and I'm not certain it was ever used on the 2.9L).

With that said, it is not out of the ordinary for new fan clutch to be bad and not disengage, so that could certainly be the cause of the fan continuing to turn and roar even when it shouldn't be doing so. I've had this exact scenario occur myself, where the manufacturer didn't properly clean after machining the parts and before assembly, and bits of metal embedded themselves and prevented the fan from properly slipping against the clutch.

 

I have an 07 Colorado with a 2.9L
The fan runs super loud whenever I accelerate and increases as my RPMs increase. It does NOT overheat and seems to drive fine otherwise. So far I’ve replaced the fan clutch and the coolant temp sensor but no dice… it’s not throwing any error codes. I don’t mind having to replace things since I just got a great deal for it from my boss and know that it needs some love, but I’d really like to be able to pin point the problem without having to waste time and money replacing 15 things that don’t need replaced. Any advice would be greatly appreciated.

honestly that could make sense.. I mean I do need a new belt as it is. It has tiny fissures all over it. Might as well try changing the idler pulley. The good thing about changing the other parts is Atleast I know those parts are good now and I have the old ones for backups lol.

 

Cheap thing first, idler pulluy. If still loud, tensioner. A bad belt would squeal not roar. Possibly a bad water pump bearing, but try other things first. A new belt is in order anyway on a 2007 truck. While the belt is off, rotate each of the components to feel for roughness in the pullies.

 

I guess I'm still trying to figure out what the problem is.

Is the problem that the fan runs all the time and never shuts off?

Or do you think it's too loud when it's operating?

 

The problem is that it’s too loud when it’s operating. The noise increases as the RPMs increase. It’s not really noticeable when idle.

 

Garbage trucks are very loud, so I am going out on a limb here and guessing it's much louder than normal 😂

 

Not sure if this truck has a viscously fan clutch/fan, or electric cooling fans. If a fan clutch and plastic fan, I have seen the plastic fans crack around the mounting hub and cause noise.