HDD loud

Whilst the HDD is spinning it produces a very loud noise, almost like a fan which is why I checked every fan before finding out it was the HDD. I have taken it out of the case and put it back in to see if it was a vibration and the HDD wasn't seated properly but there was no change. I am 100% sure that it shouldn't be this loud as after not opening a single application on the HDD for a couple of hours it becomes quiet or what I think is the normal sound for a HDD. This makes me think it isn't a fault with the HDD and it can become quiet so I think it is some software that is keeping it running. I have also checked the HDD on CrystalDiskInfo which says it is 'Good'. There is also no clicking noise or any other noise coming from the HDD so I doubt it is failing.
I just can't find the problem and it is rather annoying. My HDD is the Western Digital Caviar Blue 1TB

Is it new? If not has it always made that sound?

HDD's shouldn't sound like fans.. If your hearing it over everything else, RMA it, i wouldn't trust it with your data.

RMA would be a good idea, if it is still within warranty. http://www.tomshardware.com/answers/id-2293487/blue-1tb-loud.html This may help. Other users seem to report the same with this model. Could have been one of the drives affected during the Tsunami that hit Taiwan and there had to be a switch over to Chinese factories for a little while.

Quido I just ran into a situation like yours but the funny thing is I have a Seagate hard drive in my pc along with the so called top dog Western Digital Caviar Black hard drive and I was thinking oh no I am going to regret going Seagate as it is likely the one making so much noise but nope it is this 640 GB Western Digital Caviar Black I got just less than 5 years ago that is the problem and here is the real kicker ..... eh when I looked at my receipts in my email for this drive I noticed I had gotten the original one D.O.A. and so when I RMA this hard drive this time and get a new one from Western Digital I will be on my third 640 GB Western Digital Caviar Black hard drive. Oh and btw use the Data Lifeguard Diagnostic for Windows or whatever OS you have from Western Digital to find out the problem. I ran the quick test and got an error code that said there were problems with the drive reading properly. Best of luck with your pc hardware problem and hopefully for you well you don't have to RMA to Western Digital as that will definitely be out of pocket to send it. Hopefully you still have a warranty still good with the store you bought it from as sometimes they cover shipping both ways depending on how long you have had the hardware.

When a HDD is making a 'odd' sound then its likely the start of a failure - backup and return

How old is this HDD? really old models aren't all that quiet.

So Quido what happened in your situation? Did you RMA it and did they make you pay for it? Supposedly Western Digital created a label for me to use with UPS to send it in for free but I need to print it off and then spend my own money and use whatever I have to ship it properly. I ended up complaining on Facebook about how companies make us pay for RMAs and then Western Digital Facebook responded to my post and said someone would get in touch with me by email and they did. It is nice to see a company understand that current RMA policies maybe need some changing and cost shouldn't all fall on the consumer or in the future not at all. Anyway hopefully what they paid for with UPS is still good as I have dragged my feet in getting this RMA done. I had hoped when they said they would pay for an RMA they would just drop off a box for me with a label included to ship back but nope. Eh anyway for future reference people you should complain about RMAs and how they are done now as it may save you a buck and may bring change.

... and in regards to the hard drive that is a problem I am still using it and it definitely has it's issues. It makes horrendous noise at times still. There may also be another issue the hard drive is causing and I will know more in the next hour or so as I am going to test a theory of mine.