Hi this is my first AIO I am having a very weird issue and have no idea what it could be. I had this AIO for 5 days. The first 3 days I tested while gaming on my 9700k (stock) and My fan runs constantly at 1020 without custom fan curve by default. 3 days ago On Rainbow Six Siege 1+ hours of gaming it didn't go over 65c same for Rust max after 7 hours was 66c. However yesterday and today my temperature started reaching 70c from hours of playing Rust. I was very impressed at first with this cooler because it was outperforming my Noctua NH-U12S by almost 5-10c in games I don't know what happened but is now under performing.
 
I have no idea if i should request a replacement from Newegg. I am really not comfortable with my temperatures been higher than an Air Cooler because this just started 2 days ago before then it was amazing by my standards having used nothing but Air Coolers for the past 5 years. I was so happy with the initial results and temps. No idea what happened yesterday and today.
During RealBench 15-30 minute Stress test I was reaching 74c 3 days ago today I hit 80c. Pump is running full speed via flow control usually sits around 2800-2940RPM
 
I know I can increase the Fan speed and set custom fan curve but the fan sits at 1020 constantly under any temperature but that wasn't an issue 3 days ago as its always been the same since the first day. However I noticed that in RealBench after 30 minutes the coolant reached 48.5c is that normal as well?
 
Would love to have my original temps back again. Not sure if I should try my luck with Corsair or just get an RMA for this one while I am in the 30 day period through Newegg.
Also my idle temps the first 3 days were 28c now its 30-35c
 
Sorry for the long post but maybe someone with some experience can make some suggestions.
 
Thank you!
 
(EDIT: the signature on my post is old I need to update it that's from 2012 hehe)

sparetimepc
So in the past few days has your ambient temps increased because of warmer weather? Are you playing on max settings ? Where do you have the CPU cooler radiator mounted at ?  You can't really say the cooler is defective if your not speeding up the fans to what the potential is for them to help keep things cooled down. 

Ambient temperatures has been the same around 70c no major changes recently in weather or the indoor temps in the house. CPU Cooler is mounted on top as intake. I am not saying 100% is defective just don't know what the issue is very tempted to send it for a replacement. I been running the same stock speed the whole 5 days and my temps were amazing (I never had an AIO before was very happy) yesterday and today I noticed my CPU temps increased 5-8c from the same games I played. Rainbow 6 Siege was peaking at 60c after an hour or two for the past 3 days. Today I just played for 40 minutes and my temps were 67c both when it was 60c to now the fan's were default speed.
 
Tempted to buy Corsair H100i PRO but honestly I was so happy with this cooler I don't know what to do. 
 
 

sparetimepc
Some people also remove the stock fans and replace them with high performance/higher rpm fans as well to help the cooling.

You know the stock fans aren't terrible at all they are very loud at full speed but that's expected at 2500RPM. I spent the passed hour looking up information on the CLC 240 and reading reviews online and vast majority of users say the same thing idle temps 23-28c and Load temps specifically for the 9700k stock is below 65c which is the exact same results I had 3 days ago before I had any issues.
 
I honestly was impressed with the results of this AIO. I decided after doing some comparisons online that I am going to keep it instead of refunding for the Corsair H100i PRO RGB. I am just gonna send it for a replacement. When I had no issues this AIO was amazing. No clue what happened the past 2 days. My idles are 38-40c right now.
 
Oddly enough I was running real bench today for 30 minutes and restarted the Computer after the test to cool down the AIO and the computer powered on and off then BIOS said it had an issue loading Windows if I wanted to load optimized defaults. No idea why that happened. Just clues to something been wrong not sure if its the Cooler or something else but all my parts are only a few months old. However the computer has been 100% stable the past 12 hours or so, even ran a couple more of stress test no issues other than the temps been higher.
 
Anyway gonna request a replacement from newegg. This cooler is amazing, hope this fixes the issue.