Closeable outside door vent?

If you are getting 'hot engine' smells from garage, and there isn't a running engine in there, you need to find out where the smell is coming from and FIX it, before the carbon monoxide KILLS you. A water heater should NEVER smell. I suspect you have burner troubles, or a clogged vent stack affecting combustion. Unless your garage door is super-tight, garage should be leaky enough to provide plenty of combustion air without adding a vent grille. (Since W/H is in garage, I take it you live down south?) Quick check- leave the big door open and the hot water running for awhile, to force a long burn. Do you still get the smell?

Seriouly, guy, get it checked out. Even if garage ceiling is closed in, a water heater out there, and the vent stack (if needed) should be trivial to change, and relatively inexpensive labor-wise, compared to in an interior closet or basement. Are you sure smell is from garage, and not, say, kitchen stove, or exhaust fan? Smells can be very deceptive, collecting in areas of poor air circulation.

aem sends....

Fix it correctly. Place an vent in the door and one into the attic for fresh air. That is what is required by code. Vents should not be closed for any reason. If your not to far from an outside wall vent it directly to the out side and the ceiling and forget the vent in the door. Call a plumber for specific code issues where you live as for an estimate

ok but my original question remains - where do I find such a door vent?

And no the smell is not dangerous in any way - it is just hot engine and is only a problem if I close the garage door before the engine cools down.

Bill