Loud Engine Fan

[wilson234]

2011 QX56. Typically when the AC is turned on or is on, I get a loud fan noise that goes up and down based on the engine rpms. It will eventually go away, but sounds almost like the engine is not shifting into the next gear.

What could this be?

 

[cbkqx56]

is this usually around the time you start the car, and it sort of makes it sound like a truck? that's a fan in the engine and is normal.

 

[marctronixx]

yes that is normal.

 

[NDDavo]

Hey all, long time lurker, first time poster. First off, thanks for everyone who posts. I have a 2011 QX56 that we have owned for about 8 months, just yesterday the engine made a loud whirring noise like a semi truck, and seemed to shift a bit later than normal. I didn't think to toggle A/C but this morning the engine sounded normal. Based on the sound/further description: if it had an electric fan I would guess it was stuck on high but of course it doesn't, and the loudness/pitch was directly related to the RPMs. Again, we have had the vehicle for a while now and have run the A/C plenty, any thoughts? This post is the closest I could find to my issue, but it certainly doesn't seem normal. Thanks again all.

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[marctronixx]

In short, what you are hearing is NORMAL.

The clutch fan has vicious fluid in it. When the spring warms up form the heated air blowing through the radiator, the fluid runs through these channels in the fan and the fan rotates.

Yes it moved with RPM. Yes it robs power and makes the car feel sluggish a bit. The fan is sucking a LOT of air through the radiator to cool the fluid.
After the air is cooler, the spring tightens back up and the fluid stops moving in the fan channels, and its stop rotating with the engine rpm.

Its normal.. i rather Love the sound as it sounds like a mac truck.. RROOOOAAAAARRRRRRRR...

 

[NDDavo]

Copy all and that makes sense, but why hasn't the vehicle done this before, despite driving/idling in hotter conditions for longer? Was the clutch malfunctioning before or is this full speed condition fairly rare for it to go into? Thanks again.

 

[marctronixx]

since im not in front of your car its hard to say, but perhaps the temps were not hot enough. its not supposed to be 0n ALL the time.

 

[Freddieq80]

Looks like this will be a new problem. My 2018 QX80 sounds like a big semi tonight on my way to work. I've had it a year and a half and this is the first time it stayed reved up like this. It stops about 10 seconds after I turn off the AC.

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[marctronixx]

its normal.

now you may have an issue with your engine. could be overheating, could have low refrigerant or overfilled if you did some recent work on it, etc etc, the clutch fan is doing its job, thats why you hear it. you should be able to spin it freely by hand when the engine is off.