Not only does this chrome oil breather cap look good- it serves a purpose too! Featuring an embossed outline of the infamous Chevy BowTie logo, this chrome Chevrolet oil breather cap vents blow-by gasses and fumes while adding a little chrome eye-candy to your engine. Up inside the inner ring of this oil breather cap is a wire mesh filter that allows ventilation while capturing blow by sludge to keep it from leaking out all over your engine as they would with an oil filler cap. This chrome Chevrolet oil breather cap was designed for early model small block engines with an oil filler tube. Installing the push-on chrome breather cap is simple and involves just pushing it down on the tube. The diameter of this oil filler cap is roughly 2-7/8 inches across and should stand about 1-1/2 inches when installed. Not only does this chrome Chevrolet oil breather cap look good, you also get the peace of mind knowing it’s a genuine GM/Chevrolet accessory! If you want to replace your oil filler cap with something chrome-plated and good for your engine, then you can’t go wrong with the Chevy BowTie oil breather cap! GM # 12341990