Bit of a long winded post. Apologies in advance. Couple of months back I upgraded from my i7-5960x to a Ryzen 3960x. Finally well worth the upgrade. The Intel processor was around 5 years old and I simply re-used my watercooling loop with an EK-DDC XRES-CSQ and a single 360mm radiator in the roof of the case. Fluid was Mayhems pastel ice white. I stripped the CPU block and was pleased to find that the Mayhems fluid had left very little residue over 5 years and the rest of the loop was similarly clean so after a flush and some new tubing, I put it all back to work. Haven't bothered overclocking the CPU and stock temps were a maximum of 78°C under load and 50°C at idle. In my opinion, not enough headroom to overclock so I decided to upgrade. I ordered a 280mm radiator for the front of my case, to act as the second cooling stage after the 360mm in the roof. I also ordered a full set of Arctic "P" fans to replace the my Corsairs which I am not too impressed with. So I drain the system and add the extra rad, everything goes well. I'm sticking with flexible tubing because it's so simple and easy to work with. Fill everything up and jump start the pump. Can't get it to prime. I try everything, rotating the PC to work out the bubbles, varying the fan speed, stopping and starting the pump. The loop just won't prime. Start to think that I have a dodgy radiator, so I take the new 280mm radiator out of the loop and still can't get prime. Bubbles everywhere and just a trickle of circulation. I spend hours trying to bleed the bubbles out and nothing makes a difference. 5 year old pump. That must be the culprit. Quick look online tells me that I will need £150 to buy a suitable replacement so I figure I will strip down my existing pump and look for problems - hoping to find something stuck in an impellor. The pump looked like brand new. Impellors still sharp and motor turning freely. No foreign objects. Stumped. Decided to drain my fluid and give the system a flush with previously boiled tap water, see if I get anything back as you can't see much in the pastel fluid. As soon as I drained off my fluid and added water, the system caught prime and ran perfectly. The old Mayhems fluid was the problem. I've now added my extra radiator back into the loop and filled it with distilled water. New load temps are down by 10°C and I have a happy idle temp of 35°C so it's time to start overclocking. I was too tight to buy new fluid because I thought the old was still good. Lesson learned. Cost me two full days of head scratching.
If I'm redoing/changing a loop I'll always drain and flush out the old coolant, replace the tubing, clean the loop with mayhems blitz part 2 (cleaning solution) then once that's drained and been thoroughly rinsed, fill with new coolant. Gotta get it clean and get some fresh stuff in there.
What do you use for fluid? I'm tempted to stick with simple distilled water with inhibitors. Someone on here referred to the coloured fluids as "vanity fluids" which I agree with.
I currently have ek cryofuel clear in my loops, but previously had used mayhems pastel red, white and orange without any problems. I had the white in my system for 3 years without issues, just flushed with blitz part 2 and put the orange in.
I've been using that for years no problem, although after 5 years on my previous run is started to sepperate a bit.
Pastel fluid is fine depending on how hard you push your system and for how long. 5 years without changing the fluid is a bit too long.
