After my first oil change my engine sounds a bit louder, like I got a aftermarket air intake for it. Anyone else noticed that?

 

did you do the oil change or was it done at a shop?

if it was done at a shop this is most likely what happened, the guy did the routine check on fluids and tire pressure and air filter check.

when he opened the box to get the filter out he opened it too much, unlatching the latches at the bottom, this is very unnoticeable, he then put the filter back in and closed it up.
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the loud noise you are hearing is your airbox not properly sealed. it is a pain to get it to close right .

if you took it to an oil place this is what happened.

 

i personally think the shop used some high decibel oil which would obviously make your car louder