Ima convene a panel of folks. For next V6 Tacoma oil change.
Stand around HOT engine with 1 year oil. Listen.
Then I do an oil change.
Stand around cool engine with new oil. Listen.
You be deaf if you cannot hear the difference. Much much more quiet.
You are changing the substrate, no?
A better test would be cold engine old oil, cold engine new oil.
Otherwise you are introducing a substantial uncontrolled variable with engine temperature, not to mention any recency bias, location differences, etc.
I do noise monitoring regularly as part of my job. This is a lot like Santa Claus, if it makes you all feel better then who am I to ruin your fantasies.