Question Radiator Cleaning Tips


Nov 27, 2001
I'm curious if anyone has any surefire or really effective methods for pre-cleaning a radiator.

I ask because I'm not sure if I'm just making the task harder on myself, or if it's just par for the course. I usually do a vinegar soak (100%) for about 12 hours, which was then followed up with water-filled shakings that would usually last for 30-60 seconds. I typically use tap water in the beginning and switch to distilled later. In the past, I've also heated up the water prior to putting it into the radiator for shakings. When done with any shakings, I dump the water into a white ceramic bowl to look for flakes. The problem is that I end up having to perform an inordinate amount of shakings to get no flakes. I like Hardware Labs' L-Series radiators, but it literally takes me three dozen (or more) shakings just to get no flakes. (I'm curious if Corsair's XR series is cleaner given they're just HWL's L-Series with a Corsair badge.)

I've seen people suggest using a garden hose to force the gunk out, using things like Mayhem's cleaners, or using a temporary loop with a filter. I haven't tried the former two, but I have tried the loop with a filter, and I didn't notice anything caught. Albeit, that might also mean that I'm going a bit overboard with the number of shakes; I mean... if the pumps can't force water fast enough to dislodge the small flakes, then would an actual loop have an issue?


Diamond Member
Aug 11, 2001
Are these flakes, corrosion you have caused by soaking it in acid (vinegar), or are they fungus? If fungus, I might try an enzymatic (non-acid) drain cleaner.

What is "pre-" cleaning? Would not it be post- cleaning?


Diamond Member
Dec 10, 2010
I am unable to find what these radiators are made from. Their docs say that they have copper fins, but they don't say what the tanks or tubes are made from. Typically they would be brass or aluminum.

But if this is happening to you on a regular basis, it makes me think of a few possibilities.
1: There is some current in the coolant, resulting in electrolytic corrosion. This can also happen if anti-freeze goes bad.
2: Whatever you are using for coolant is becoming acidic over time. Or using an acidic cleaner, like vinegar.
3: You may be seeing what is typically referred to as erosion corrosion. Which is where the coolant is moving fast enough to wear away the oxidized layer on the outside of the aluminum, which then makes it susceptible to corrosion. And since aluminum only oxidizes when its in contact with oxygen, once that layer is gone, it won't return until the fluid is drained.
4: Less likely, but indifferent metals can cause this. But that normally requires the coolant to have metal that reacts with aluminum in it.


Cases and Cooling Mod PC Gaming Mod Elite Member
Super Moderator
Sep 28, 2005
What flakes are you talking about?
You shouldn't get any flakes after the initial flux cleaning done on a new rad.

HWLABS are brass tubes, never aluminum.
Infact all but a few koolance radiators are brass or copper, mostly being brass then full copper except a few like the NeXXXos series.

And no i am thinking those flakes might be from a premix, or a dye deposit.

Personally i just let the rad run in a bucket with tap water with a tube res filled with filter cotton if the rad has been used in a premix coolant situation.

Then i will let it sit in distilled vinegar for about 30 min, and then flush the radiator out, with tap water, followed by a good rinse with distilled, then immediately Cap the inlet and outlet ports so air doesn't immediate oxidize the interior after.

But care to show me pictures of what these flakes are?
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