Mobil 1 Logo with trademark
Mobil 1 RacingTM
The Oil That's Changing Oil

My Mobil
Discover the Benefits of Membership
Forgot your username or password?

YouTubeMobil 1 Merchandise
Mobil 1 Rewards
Do-It-Yourself Projects
Clean Those Dirty Cam CoversPrintable version
Degree of DifficultyEasy
Estimated Time90 minutes
90 minutes
Going Under Cover
Step 1
Before you start, purchase a replacement gasket set and some sealant. See step eleven for details.
Step 2
Get the service manual and open it to the requisite page. Every engine is different, and you’ll want a reference guide to show you things. Do you know the proper torque value and the torque pattern for the cover bolts? If not, get the manual. Many municipal libraries have complete collections for check-out.
Step 3
Always disconnect the battery before starting any engine work. Remove anything that may be in the way of the cam/rocker cover coming out. Those items may include the PCV hoses, throttle cables, spark plug wires, and the air cleaner hoses and housing. Label every hose and wire with colored tape or a paint pen, as you may forget what goes where when you’re all done.
Step 4
Undo the fasteners holding on the cam cover and put them in a dish for safekeeping. This may require some unexpected tools, such as deep sockets or thin-wall sockets. Modern engine compartments are cramped, forcing engineers to get creative with how they arrange the fasteners. If the cam cover won’t budge, do another check around to see if you missed a bolt.
Undo Fasteners Holding on Cam Cover
Step 5
If you’re very lucky, the cam cover will pop right off. If it has been there a long time or was put on with an adhesive sealant, the job of removing it may get tough. Try tapping it gently with a rubber mallet all around the base of the cover. Never use a metal hammer, as you will dent a stamped-steel cover or crack a plastic or aluminum cover. Tap close to a corner, where the seal will be the weakest. If you lift the cover in the corner, get a flat object such as a broad screwdriver or paint scraper (or an actual hook-shaped seal remover, if you have one) underneath and work it around the gasket as you lift up. Work slowly and cautiously. A screwdriver can easily gouge and permanently damage a soft aluminum cylinder head casting. Apply only gentle pressure until it is off. This could take a while.
Step 6
It’s off! Now behold the clockwork innards of your engine, which may be seeing daylight for the first time since it was built. If your engine is overhead cam, you’ll see one (called a single overhead-cam) or two (a double overhead-cam) long, straight shafts with what look like eggs stuck on them. These are the camshafts and cam lobes which open the valves. At one end of the camshafts will be a sprocket for the timing chain or timing belt. Now is the time to inspect the cams and valve gear for wear. You won’t be able to see normal wear, which happens in the thousandths of inch, but you can look for obvious trouble signs. Those include burnt cam lobes, spalling (flaking) of the lobe’s hardened surface or pitting of the lobe. All of these are signs of advanced cam wear, which will have to be addressed by a professional mechanic.
Viewing Engine Interior
Step 7
If your engine has solid or non-self-adjusting valve lifters, this would be a good time to check clearances and adjust the valves. All engines are built with a certain amount of slop, or space, between the tappets – which press the valves open – and the actual valve stems. As an engine ages, the valves recede into their seats, closing that gap. Most new cars have self-adjusting valve lifters. If yours doesn’t, check your shop manual for the correct procedure on how to check and adjust. Depending on the car, this may be one job for the pro mechanic. Note: do not run the engine with the cam cover off. Oil will fly everywhere.
Step 8
If you’re working outside or in a dusty place, take a drycleaner bag or garbage bag and put it over the exposed cylinder head to keep grit from getting in the engine.
Step 9
Clean the cam/rocker cover. Use an old deep-dish baking pan or a disposable aluminum foil turkey pan from the grocery store and pour in a few cups of mineral spirits or lacquer thinner (both available by the gallon at home stores) to dissolve the grease. Wearing chemical-resistant gloves to protect your skin and safety glasses to protect your eyes, clean the cover inside and out with an old toothbrush or paint brush. If the cover is aluminum, don’t use a steel brush, as it will gouge the aluminum. A brass brush or a stiff-bristle brush and a plastic scraper is good for removing the old baked-on gasket. Properly dispose of solvents. The best way is your city’s household hazardous waste drop-off site, which is usually free.
Step 10
After the cover is degreased, it’s time to decide if you want to paint it, replace it with an aftermarket cover, or just stick it back on. If you paint the outside of the cover, you’ll have to further clean the cover to remove all trace of oils and residues from the degreasing agent. Most auto parts stores sell a pre-paint degreaser that does not leave a residue. Use a clean cloth, and don’t touch the cover with your hands as even the natural oils on your fingertips can cause the paint to “fish-eye.” Most auto parts stores sell a variety of colors and finishes in spray cans. Options: paint the cover the same color as the body. Paint it red. Paint it black with the manufacturer’s logo polished up or hand-painted in red. Krylon markets a line of spray-on wrinkle finishes that will give your cam covers the same look as a Ferrari’s. For best results with wrinkle paint, follow the direction on the can to the letter. Plastic covers will be harder to paint. You must use a paint that is compatible with plastic, such as hobby enamel, though it may not wear as well over time.
Paint the Cover
Step 11
Time to reinstall the cover. You will have purchased a gasket for it already. The gasket may be made out of cork, paper, or pre-formed silicon. The latter is by far the best, though it costs the most. If the auto parts store gives you the option, consider spending the extra money on a pre-formed silicon gasket. They are molded to fit the shape of your cover, often have steel bolt eyes in them that prevent over-torque of the bolts, and do not require a gasket dressing.
Step 12
Reinstall the fasteners and reattach the loose hoses and cables.
Return to list of articlesPrintable version
Page:  1 | 2 | 3
Copyright 2005-2014 Exxon Mobil Corporation. All Rights Reserved. ExxonMobil Home | Site Map | Contact Us | Privacy | Legal