MX-3.com

What is the function of the rear air vents in the MX3?
Im thinking of closing mine up because I think they may be the main reason why so much noise gets in the car.

There there to help vent the trunk, - i know obviously - but i was told (They also help relieve the pressure in the car when shutting the doors with all the windows closed. All cars have them somewhere)

also vents exhaust gas -helps-

the vents are to let the cabin air out. Air comes through the cowl in front of the car, out the vents in the dash, through the rear deck into the trunk, then out the vents in the trunk, in theory. They simply allow air to circulate through the car.

NOTE: mine are closed off currently with dynamat sound proofing material because really i do not care about the vents at all, truth is, there is very loud flapping sound every time I have my system loud becuase of the bass. It make the flap move so fast its a plastic to metal sound.

i have closed them up for 2 months with no noticable issues but winter time i may reopen it up for the ventilation with the colder weather?!

They just let air escape.
They shouldn't let much noise in the car. I never noticed. One of mine was damaged when a lady backed into my RS. I picked one up from a salvage yard but the body shop didn't bother replacing it.
It doesn't vent exhaust gas. You shouldn't have exhaust inside the car anyway... I had exhaust gas entering the cabin with the broken one still in place. I replaced it during a semester of auto body, and no more smelling exhaust when windows and moonroof were closed!
I don't really think covering them up would be too detrimental, other than the momentary buildup of air pressure when shutting the doors, may make that tricky.