Suddenly Loud fan and slow

Two days ago I was about to start working on my laptop, it took a few minutes to boot and started fanning like crazy. This was absolutely unexpected. The day before it was working like a charm, didn’t spill anything on it and it didn’t get hit by anything.

The fan is spinning at max (6500), and the cpu is taken over (400-800%) by kernel_task.

I have tried pram resets and smc to no avail. Smc did give some sort of results, as in once in a while it makes the computer fast again, mak s the battery disappear (isn’t recognized both by coconut and my os), but the fan is still maxing out. In addition to that I used disk utility and ironed out a few bugs in the system. The volumes are now perfectly fine.

On the hardware side I pried open the thing, pulled out and put back battery, io/cable, fan and ssd. A hardware test was run, it didn't find anything out of the ordinary.

All that didn’t get me anywhere. I’m willing to substitute i/o board and cable, but am not sure wether or not it’ll be a solution.

Any inputs are more than welcome.

I did run diagnostics, the results were:

• Battery will need to be replaced soon (functioning normally) PPT002
• There may be an issue with SMC, PFM006, PPN001

TG Pro says 6500 rpm (as I said), and no part of the laptop is over 45 C. The hottest being the SSD at 45.

Update:

I pulled the logic board out, the backside doesn’t show any signs of corruption of any kind. It was submerged in dust though. I’ll clean all the components today. Battery lufe cycles will be posted.

Update:

Coconut gave back 1300 lifecycles, making the change 300 lifecycles overdue. Still, can the battery cause this kind of errors?

Update:

Running the system without the battery gives the same exact results as with.

Update

Just to be sure I cleaned my ssd an reinstalled macos. It was to no avail. Utility monitor doesn’t show kernel_task taking over anymore though.