Question Burnt smell coming from the watercooling?

[Chiliji]

Hi,

I am sorry if my post does not conform to rules on this forum.

My rig is a bit more than 2 years old ( Jan 2022 ).

My components are as such:
- GIGABYTE X570 AORUS MASTER ATX
- AMD Ryzen 9 5900X
- MSI GeForce RTX 3060 Ti GAMING
- CORSAIR DDR4-3600MHz (4x16)

As watercooling unit I have a Corsair 360mm iCUE H150i ELITE CAPELLIX.

30minutes ago while turning on my PC, it reached the user screen and just shut down in an instant.
Thinking I somehow did not turn it on, I turned it on again and this time less than 2 seconds before it completely shut down again.

I decided to take a look and somehow I could get a smell coming from the fans of my watercooling unit.
I unplugged everything, opened the case to take a look.

Thinking it was the CPU that burned somehow I put my attention towards it mostly.
When unplugging the WC from the CPU I noticed that:
- One cable from the WC was burning hot while the other was ice cold.
- The burning smell came from the big water block.

My CPU does not appear to be burned and was not hot to the touch.

I would like to get some advice on how to proceed as right now I could not even check the temperature as I could not turn it on for more than a second.
Is the CPU likely to be the case? Should I try turning it on without my WC? Should I just go ahead and buy a new WC?

 

[punkncat]

Are you blowing dust out of the cooler on a regular basis?

Mine will get a smell much like turning on the heat the first time of the season if I don't clean it pretty regularly.

 

[Chiliji]

Yeah I usually do dust off my whole PC every week or two weeks as I live in Tokyo and it gets pretty dusty here.
I don't think it smells like a heated thing, 2 hours later and with everything off circuit and cooled I still get a burnt smell from the waterblock.

The smell also is not located at the copper layer which is in contact with the CPU
but it's towards the top of the block

 

[Ralston18]

PSU: Make, model, wattage, age (2 years?) Original to build, newer, refurbished, used?

 

[Chiliji]

NZXT C850 - Aged 2 years as well , originally new​

No abnormal smell or heat from the PSU when the problem occurred
https://www.amazon.co.jp/gp/product/B089536LJ1