GM Performance 12590366 Driver Side Valve Rocker Arm Cover 3.0L 3.8L

The GM Performance 12590366 is a Genuine GM Driver Side Valve Rocker Arm Cover (also referred to as a rocker arm cover or valve cover) designed as a direct OEM replacement for GM vehicles equipped with 3.0L and 3.8L engines. This cover seals the top of the cylinder head, protecting the valvetrain components — including rocker arms, pushrods, and valve springs — from contamination and oil leaks.

Key Features:

• Genuine GM OEM Part — designed, engineered, and tested to GM's rigorous quality standards
• Driver Side (Left) fitment — mounts on the left/driver's side cylinder head
• Engine compatibility — fits 3.0L and 3.8L engine applications
• OEM replacement — replaces obsolete GM part number 25534753
• Ensures a precision fit, maintaining a proper seal to prevent oil leaks and engine contamination
• Restores factory form, fit, and function without modifications

GM Part Number 12590366 is also cross-referenced under the ACDelco GM Original Equipment line. This part is also known as a valve cover, rocker cover, or cam cover depending on application. It supersedes OEM part number 25534753.