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 questions I had was how do the cooling fans 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

 

I just had that on my 05 with a hemi and couldn't find it. I thought I checked everything so I gave up. Three weeks later my serpentine belt starts shredding and when I get it to the shop they told me my idler pulley was bad and had to be replaced. I would be sure to check ALL of the pulleys on the front of your engine.

 

My 06' has been doing the same thing for years. No reason i can find to why sometimes the fan is engaged and sometimes it's not. But since it has been happening as long as i remember and at least the last 70k miles, i am not too worried about it.

 

Ya it doesn't seem to act like anything is wrong with it its just weird how it is on sometimes at start-up and sometimes it doesn't come on at start-up. Cold or hot doesn't matter. Oh well I guess.

And I'll double check all my pulleys and the belt to make sure they are in good working order!!! Thanks for the heads up!

Robbie

 

I had a whirring sound coming from my engine most times until it ran for a while, did it from the time I bought it. Bought it used. Sometimes never went away, other times it was always there. Just thought it was normal. Then one day when accelerating the amp gauge dropped to zero and check gauge light came on. Let off accelerator, gauge came back to normal. Would happen every couple weeks or so. Replaced alternator, this fixed the whirring sound and amp gauge issue. I am guessing the bearings were not right in the alternator.

 

I've heard of these trucks having problematic alternators. The sound I have is more like a fan blowing air than anything else. I'll keep my eyes and ears on it to make sure nothing else seems to be going on. Thanks for all the responses!

 

The sound i am talking about is unmistakabley the fan. It's a sound like nothing else. If you have any doubts, lift the hood and it will be obvious. I too have heard of Alternator bearing issues, but having heard those sounds on other cars in the past, they sound nothing alike.