Here is all the info in the service manual about fans:
6-2 Samsung Electronics
Internal noise may be caused by a foreign substance on the fan or driving device.
For a DLP TV, the LED fan, DMD board fan and Driver board Fan are vulnerable to noise. Sometimes the connector wire around
the LED or DMD fan makes contact with the fan, When irregular noise occurs for no particular reason, check the inside of the TV
for any foreign substances.
The DLP projection TV may cause noise as the physical screen is empty inside, causing a resonance of a particular frequency.
Thus a low vibration is not a malfunction.
Any 'creaking' noise is mostly from the structure of the device itself. A short, harsh noise may occur from a distortion or
malformation due to thermal expansion between the metal
Not sure if each LED has a fan, but it seems like there are three fans. You are probably safe as long as the fans are working. Sure they may be noisy, but they are at least cooling the parts. I'd be more worried if there was no fan noise. If it is really loud you may just want to open up the back panel and see if you can get to the fan making the noise easily.
Hopefully someone who has done a fix like this will reply as I have yet to open up my set for any reason.
Here are some parts from samsungparts.com:BP31-00022B
FAN-DC / LAMP FAN #2BP31-00025B
K880 DLP TV(LAUREL),BALL,12V,70MA
Nationwide BO Specification