Seidon 120v v3+ have some scratching and worried RPM Drops , Can I change the fan?

[MindUnited]

The Seidon 120v V3+ (120mm AIO) has made some Scratch Noise? It makes me very worried now

 

This is how it sounds 

 

occuring with this , the RPM of "FANIN4" Will drop. Normally around 2045-2102 RPM , when drops to around 1900-1800rpm it have a  noise and when it downs to 1600 rpm or sometime even under 1000RPM it produced these scratches

 

I did check there is some dust behind these XtraFlo120 Fan Blades. I'll wipe tomorrow to see if it fixed

 

So Far I have observed that 

1. It happens randomly , cant catch a pattern. First its occured during a game of DOTA2. Now Randomly , even someday it wont happened at all

2. The Temps are still normal. it stays in 25-30c in Idle and 35-45c during gaming 

3. I assumed that this FANIN4 will be the Fan In video. As this picture shows

4. Starts occuring since February 10. Still fine to today

5. I have put ear beside the case , Its from the AIO Area. I thought its the HDD at first but no. Not the HDD

6. During This thread was created. it still happens randomly

 

 

At First I thought FANIN4 was pump , as it shows "Power Fan" in Gigabyte 970A-D3P Motherboard.

 

But once during this issue have the fan drop down to visually almost stop spinning before it backs on. So FANIN4 is the Front Fan of Radiator

(CPU are Pump , FANIN1 is the back of raditor fan , FANIN2 is the Front Case fan << nothing with it)

 

Ok , here is the question I'm here for  
- Can I switch the fan of this AIO with other one, How do I know it's compatible or will work fine with it? and since it's a push pull - It needs to be the two same fan right?

http://eu.coolermaster.com/en/cooling/cpu-liquid-cooling/seidon-120v-v3-plus/  - The CFM for XtraFlo 120mm Fans are

Fan Airflow	36-86 CFM ± 10%
Fan Air Pressure	0.41-2.87 mmH2O ± 10%

- Or the only go to is change to another AIO (i'll talk only AIO here , no Interest of the Air Cooler at this point)

 

Here is my PC Specs in case if needed

CPU : AMD FX-8320E 3.2ghz (Have not do any overclock thing , I let the turbo do the thing)
CPU Cooler : Cooler Master Seidon 120v V3+ (120mm AIO) - This is since August , it serves me for almost half a year

MOBO : GIGABYTE 970A-D3P Rev2.0

VGA : GALAX GTX 1060 3GB

RAM : Gskill Sniper 8GB DDR3

PSU : Seasonic X Series 750w

HDD : WD Black 1TB

Front Case Fan : TT Luna Blue 120