Valve Cover Breather
Fits aftermarket valve covers using 1 5/16"-12 (16AN) screw-in thread, including Holley LS covers (shown)
This valve cover breather assembly replaces the original oil cap included with many popular aftermarket valve covers. The base is CNC-machined from billet aluminum for precise fit, and the included silicone O-ring is specially designed to prevent oil seepage at the base of the breather. The filter base is microfinished for surface protection and good looks, and is easily hand-polished to a mirror-like appearance. The removable filter element is a high-quality reusable unit from S & B Filters, which is securely retained in the filter base by a specially-machined retention groove in the top of the base.
The purpose of this valve cover breather is to vent unwanted accumulation of pressure in the crankcase. The installation of this breather will contribute to increased engine oil life and reduce the possibility of failed engine seals resulting from excessive crankcase pressure. Like other Metco breathers for late model applications, this breather includes a removeable one-way check valve that allows pressure beneath the breather to escape, but will not allow ambient air into the breather under high vacuum (cruise) conditions, which can impact the tune. This breather is compatible with oil separators (like the J & L unit), and does not require modifications or changes to the PCV system for installation.
Valve cover breathers are not emissions-legal.
Note: Image 3 shows this breather installed on Holley's cast valve covers for the GM LSx application. Please confirm fitment on other valve covers prior to ordering.
Valve cover breathers cannot be shipped to the state of California.