Occassional loud fan noise on start up

[Robstar]

Hey guys,

I purchased an 07 1500 5.7 4x4 with 55k miles on it about 3 weeks ago and I'm loving it! One question I had was how does the cooling fan work on these things? I know they are attached to the rotating assembly of the pulleys/belts, I'm assuming on the end of the water pump? Anyways, sometimes when I start it up it will have a loud whirring sound like the cooling fan is just blowing a ton of air under the hood and it stays like that for probably 10 minutes after driving it before the noise settles down to normal. Other times it doesn't make this noise at all. It doesn't run rough or have any CELs and if I was deaf I wouldn't even know it was doing it. It doesn't seem like a problem I was just curious if other people's trucks do this also or if maybe there is a clutch in the fan that is going bad or whatever. Any opinions, help, etc. is appreciated!

Robbie

 

[The Assassin]

Bump for ya

 

[rambob]

sounds like a period of time before the thermostat opens.

I had a chevy truck that had unusually loud fan.

 

[Ramunit]

The noise is a fan clutch. It stays engaged at startup until temps get up to a certain level. The whooosh noise is normal unless it never goes away.

 

[Robstar]

It usually does go away after I've been driving it for a while. I figured it was something like that. What I thought was weird was that the fan was engaging on cold starts. Its in the 20s here at night and it comes on when I start it up in the morning. But it doesn't happen all the time. There is no rhythm to it or only when cold or hot just whenever it feels like it. LOL.

 

[KGBIGCOUNTRY]

Just the clutch fan, depending on if you have the tow package you might hear the elec fan for the trans cooler kick on also.

 

[bigtigga84]

If you hace the climate control set to defrost the ac fan will come on when you start up at least mine does

 

[Robstar]

I switch to the defrost after it starts but even on a mid-day start-up (no defrost, just mid vents) it will sometimes do it. Like I said no rhyme or reason to when it does it.

 

[Hemitom]

Its normal...mine does it as well...since day 1.

 

[TexasRammer]

mine does it too, sometimes it can be pretty loud and annoying

 

[WhiteExpress]

It is just a very common / annoying problem of having a fan on a clutch. When it gets chilly outside my '11 does the same thing. Worry not, nothing is wrong.

 

[Robstar]

It's good news to hear it isn't a problem! Thanks for all the replies guys!

Robbie

 

[Trupiano]

My 05 fan was always a little loud for the first couple mins, but I put in an electric fan. You could always take a video so we could hear, help to diagnose if there is a problem.