How to Replace Valve Cover Gaskets
- 1). Remove the breather cap, or disconnect the positive crankcase ventilation (PCV) valve from the valve cover. Older engines without emission control systems feature a component called a breather cap, which allows oil vapors to exit from the top of the valve covers. The cap looks like a small air filter and can be removed by pulling the cap off of the valve cover. More modern engines feature a PCV valve, which is designed to draw in air and mix the air with any oil vapors that have escaped past the piston rings. The PCV valve then routes the air and vapor mixture into the combustion chambers, where it is then burned to reduce emissions. The valve need not be removed from the top of the valve covers, but the rubber hose that connects to the valve must be disconnected. The hose attaches to the valve with a hose clamp, which can be loosened with a standard screwdriver. Pull the hose off of the valve after loosening the clamp.
- 2). Remove the valve cover's retaining bolts with a wrench. The number of retaining bolts varies with the particular engine, but there will be retaining bolts within the upper and lower lips of the valve covers, and possibly on the sides of the covers. Pay particular attention to the back of the valve cover, as it is easy to miss a retaining bolt here.
- 3). Remove the valve covers from the cylinder heads. With the valve cover's retaining bolts removed, the valve cover will likely still be attached to the cylinder heads. This is because valve covers use a gasket to seal the seam between the bottom of the valve cover and the top of the cylinder head. The gasket is covered with gasket sealer when installed, and can make removal difficult. If the valve cover will not lift off of the engine, gently tap on one side of the cover with a rubber mallet until the valve cover dislodges from the engine. The rubber mallet will deliver the necessary force without denting the valve covers.
- 4). Remove the gasket from the valve cover. Valve cover gaskets are one-piece gaskets, meaning that they can usually be pulled off of the valve cover as a single piece rather than in sections. If portions of the gasket remain on the surface of the valve cover, remove the remnants with the blade of a standard screwdriver. Be vigilant here, as old gasket material can result in an oil leak by preventing a good seal between the valve cover and the cylinder head.
- 5). Install a new valve cover gasket. Apply gasket sealant to both sides of the new valve cover gasket, then insert the gasket along the lip of the valve cover. Press the valve cover onto the top of the cylinder head.
- 6). Install the valve cover bolts to secure the valve cover to the cylinder head. It can be challenging to locate the holes within the cylinder head that the valve cover's bolts tighten into. The guesswork can be minimized by threading a bolt into the cylinder head at two opposite sides of the valve cover, which will automatically align the remaining holes. Tighten each of the cover's retaining bolts with a wrench.
- 7). Install the breather cap, or connect the PCV valve's hose to the PCV valve. If the engine is equipped with a breather cap, simply press the rubber tip at the bottom of the cap into the rubber grommet within the top of the valve cover. If a PCV valve is used, position its hose over the top of the valve, then tighten the clamp at the end of the hose with a screwdriver to secure the hose to the valve.
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