2005 Nissan Altima - Valve Cover

What Does a Valve Cover Do?

The valve cover seals the top of your vehicle's cylinder head to keep debris out of the oil and prevent damage to the valve train and other components. This not only reduces the chances of valve and camshaft damage, but also allows access to the valve train as needed for service. Valve covers also keep oil inside the engine, and are sealed with rubber, cork, or silicone gaskets during installation to prevent oil leaks. Valve covers are made of many different materials, such as plastic, aluminum, and stamped steel, depending on the vehicle. Stamped steel and plastic valve covers can warp or crack due to high heat from the engine over time. Valve covers can also warp or bend if the bolts holding them in place are over-tightened, which can allow oil to leak beyond the gasket. Most valve cover gaskets will last about 30,000 to 60,000 miles, but a damaged positive crankcase ventilation (PCV) valve can cause high internal engine pressure and premature gasket damage. Warped valve covers may also fail to seal properly even with a new valve cover gasket, it may be necessary to replace both components to ensure a lasting repair. If you notice your vehicle smells like burning oil or is smoking, if the engine is running rough, or if the valve cover is noticeably cracked, damaged, or leaking, it may be time to replace the valve cover and valve cover gaskets. Replacement valve covers that match the original equipment on your vehicle are available at O'Reilly Auto Parts. Shop our selection of plastic, aluminum, and stamped steel valve covers in-store or online to find the best fit for your vehicle.