Question Highly Irritating Flushing Noise From Liquid Cooler

[emrecimLOL]

Hello,

So for a good 3-4 months now I've been having an issue with my liquid cooler. It's been making a rather audible and very irritating "flushing" kind of noise, and I know it's supposed to do it for a minute or two when booting but for me it's for a good 30-40 minutes, then once it's finally all peace and quiet it comes back again after 5 or so minutes and the cycle continues.

My case is a s340 elite, I have the Cooler Master ML240L mounted at the front as an intake and the pipe hoses are at the top of the rad. The flushing noise is VERY CLEARLY coming from the pump and my temperatures are perfectly fine too. These noises never happened for the first couple months after I bought the rad and it was very nice, but now I'm honestly thinking I should go back to air cooling as it was ironically much more silent. Any help is appreciated, thanks.

 

[drivinfast247]

Probably a stuck air pocket. With the PC running tilt the case back and forth and side to side. I'd go all the way parallel with the floor.

 

[MasterMadBones]

You should mount the radiator with the hoses at the bottom if you can. Any air left in the system will gather in the highest point over time.

 

[emrecimLOL]

I'm tempted to try that but many people say air can get trapped at the top if I do that?

EDIT: Now I do notice that my pump's Cooler Master logo is upside down indicating that the hoses should've been at the bottom, but I am still unsure.

 

[Paperdoc]

I suggest you contact Tech Support at Cooler Master. What you describe MAY be a symptom of loss of liquid from the closed system, leaving too large an air pocket in the pump reservoir. That can cause some of that air to be swept into and through the pump from time to time, until it goes all the way around the loop and returns. IF Tech Support says that is what your noise means, then they can advise how to open the loop, add more fluid (and that find of fluid to add!) and then re-seal it.

 

[rubix_1011]

What you are describing is cavitation which is caused by air being pulled through the pump. It also means that the larger air bubble gets chopped into tiny little air bubbles and will later collect into a larger one, as you've mentioned this occurs each time at startup, correct?

I'm tempted to try that but many people say air can get trapped at the top if I do that?

You mean in the end tank of the radiator? You'd rather it be here than in the pump.

EDIT: Now I do notice that my pump's Cooler Master logo is upside down indicating that the hoses should've been at the bottom, but I am still unsure

I'm not sure I'm following. If you can orient the hoses to where they leave the bottom of the radiator, this would be beneficial as the air would settle to the top of the end tank of the radiator. Also, I don't know that the logo itself really drives any of the orientation of the radiator or tubing as these coolers can be mounted in just about any location.

How much sloshing can be heard if you shake the radiator? Just a tip, if you can hear sloshing, that means there is air and more sloshing means more air. A radiator that is completely filled with coolant cannot slosh.

 

[Karadjgne]

It's a ML240L. There is no unseal/sealing. Can't open factory crimps. As new as that unit is, it shouldn't be suffering any issues with coolant levels at all. That doesn't usually happen until it's 5-6 years old. Barring leakage.

If tilting and holding the case to where the radiator is the uppermost component, and holding that position for a 10 seconds + didn't elevate the noise, you'll have one option. Dig up the receipt, rma it. Either through the seller if still under warranty, or contact CoolerMaster for the factory warranty rma.

And no, absolutely there should not be any flushing sound period. At boot up or otherwise.

 

[drivinfast247]

By having the pump head installed upside down you're preventing the air from escaping the impeller.

 

[emrecimLOL]

Okay I've uninstalled it, tried to install it upside down, case diameters and gpu didn't allow for it, so I sloshed the water around a bit and got the bubble out the pump, applied a fresh bit of thermal paste and reinstalled it with the hoses at the top. Temps are just as good as before except the noise has been completely eliminated (Except for boot obviously) and the boot only last a few seconds! So yes, sloshing the water around solved my problem.

 

[rubix_1011]

I've handled a lot of AIOs in the way of testing them for the TH site's cooling reviews. Nearly all of them sloshes a bit when handled because they are filled by machine with an explicit volume of coolant, meaning there is likely some air topping off the cooler when they are sealed. Beyond this, there should be be any further introduction of air inside the cooler or the introduction of coolant external to the cooler. In fact, several AIOs include documentation which says that some sloshing or cavitation noise can occur and does not indicate a broken cooler, although constant cavitation can lead to impeller failure over time.

While AIOs historically have not been as reliable or good-performing, they have improved greatly in recent time. I would (and do) personally use custom watercooling components and solutions over AIOs, or just use quality air coolers because this is my preference.