How to Replace the Valve Cover Gasket on a Chevrolet Trailblazerby Grace Mclain
The valve cover gasket on the Chevrolet Trailblazer is designed to prevent oil from leaking from the sides of the valve cover. The motor oil is pumped up out of the oil pan and into the crankcase. The oil then reaches the valves and the rocker arms. If the valve cover gasket has any cracks or damaged areas, the motor oil will leak out of the valve cover and get all over the engine. Once the valve cover begins to leak oil, it will have to be replaced.
Park the Chevrolet Trailblazer in a safe area and open the hood.
Locate the valve cover that has the leaking valve cover gasket.
Remove all of the bolts that are connecting the valve cover to the top of the engine block with the 3/8-inch drive ratchet and a socket. Turn the bolts counterclockwise to loosen and remove.
Carefully pull the valve cover off the engine block. Remove the old gasket from the bottom of the valve cover.
Wipe the gasket area on the valve cover well with a clean rag. Then, wipe the surface of the engine block where the valve cover gasket seats with a clean rag as well.
Position the new valve cover gasket onto the bottom of the valve cover in the correct position. The valve cover gasket is made to fit one way on the bottom of the valve cover. Put the gasket onto the valve cover in the same direction in which the old valve cover gasket was. Make sure that the new gasket is properly seated.
Put the valve cover back over the top of the engine block. Match up the bolt holes and screw the bolts into the valve cover hand tight.
Tighten the bolts down in a sequence so that the new valve cover gasket will pull down evenly. Tighten one bolt on each side at a time. Then, tighten one bolt on each end of the valve cover at a time. Keep rotating the tightening sequence until the bolts are completely tight.
Crank the engine and let it run for two or three minutes. Inspect the new valve cover gasket for leaks while the engine is running. Then, turn the engine off and close the hood.
- "Chevrolet TrailBlazer (including EXT), GMC Envoy (including XL) and Oldsmobile Bravada Haynes Repair Manual for 2002 thru 2009"; John Haynes; 2010
- Some of the valve cover gasket packages or boxes will give you the exact installation procedure for putting the new gasket onto the bottom of the valve cover. The key is to get all of the old gasket off of the valve cover and to make sure that the valve cover gasket surface is very clean.
Things You'll Need
- 3/8-inch drive ratchet
- 3/8-inch drive extension
- 3/8-inch drive sockets
- Clean rags
- New valve cover gasket
- Keep your hands away from moving parts on the engine.
- Be careful when working around a hot engine.
Grace Mclain has been writing professionally since 1998. Her articles have appeared on eHow.com, Answerbag.com and LIVESTRONG.COM, and she specializes in automotive and business topics. McIain has a professional writing certificate from JB Hunt in Little Rock, Ark.