My 01 S60 T5 is making a strange ticking noise that sounds kind of like a knock, but it's not audible from above the engine with the hood open. It's coming from under the passenger seat area.

It is intermittent and not present right away at cold start. It starts a few minutes after start up, and comes and goes intermittently.

It does increase tempo with higher rpms.

It doesn't change whether in gear or in neutral / park.

Any clues? FYI I am also showing evap codes, wondering if it's related. Additionally, I filled it up for the first time with 87 octane a few days before this happened. I'm now running with half a tank of leftover 87 and half premium. Also I was driving it pretty hard when the noise started.

https://youtu.be/pM6U1AHjde8?si=63hlWAlay-bJT2-i

Thanks!



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