Valve Cover Buyer's Guide
- A valve cover is a metal (sometimes plastic) lid that bolts over the internal combustion engine’s cylinder head.
- The gap between the rest of the engine block and the valve cover is sealed using a valve cover gasket, while a valve cover breather can be located at the top.
- Valve covers feature different construction methods, such as stamped steel, cast aluminum, fabricated, and billet.
- A valve cover that’s loose or cracked will not be able to fulfill its duty and may cause your engine to either overheat or gradually wear down its parts.
- Leaking valve covers will eventually lead to major engine problems, which means you should address issues immediately after noticing them.
- You can save money by purchasing OE valve cover replacements on CarParts.com, with options as low as $18. Meanwhile, our higher-quality valve covers can cost around $300 to $760.
Internal combustion engines are still the dominant type of engine that powers roughly around 90% of vehicles today. These engines feature cylinders that house the pistons, camshafts, crankshafts, valves, spark plugs, fuel injectors, and many more. Consisting of both stationary and moving parts, the engine is a car’s most important main component.
If you are to look at your engine, the first thing you’ll see after popping up the hood is the valve cover. Most people call it the “rocker cover” or “cam cover” simply because it’s bolted on top of the camshaft. In some vehicles, it covers the timing gears, but its main purpose is to cover the cylinder heads.
What is a valve cover?
A valve cover is a metal (sometimes plastic) lid that bolts over the internal combustion engine’s cylinder head. It makes the top of your engine look neat while protecting all its moving parts from debris and other types of contaminants. It also helps keep the oil from leaking out of the engine. The gap between the rest of the engine block and the valve cover is sealed using a valve cover gasket, while a valve cover breather can be located at the top.
Valve cover construction types
Valve cover designs vary depending on the type of engine it fits on. The most significant change that affected valve covers was when coil-on-plug engines were introduced. Since the coils in this type of engine mount directly to the valve covers, restyling them became inevitable. Now, valve covers feature different construction methods. Here are the common ones you’ll easily find in the market:
The most common type of valve cover is stamped steel mainly because it is cheaper to manufacture. However, its tooling cost may vary depending on which cylinder head it is designed for. Stamped steel valve covers are simple and would usually have zero sealing problems.
The only thing with stamped steel that bugs some consumers is that the steel is relatively thinner compared to other valve cover constructions. Because of this, they tend to easily warp, making them almost impossible to gasket-seal.
Fabrication allows manufacturers to conduct smaller production runs on highly specialized cylinder heads. It involves cutting, bending, and welding the sheets of metal to create the desired shape. Some fabricated valve covers feature aluminum welded to the rail for better gasket-sealing.
Fabricated valve covers are flexible because they are good when it comes to adding or reducing fittings as well as in other intricate modifications.
Due to the material price involved, this type of valve cover construction relatively costs more than its stamped steel cousin. That puts cast aluminum as the more expensive alternative for stamped steel valve covers. However, just like their stamped steel counterparts, cast aluminum valve covers are not designed for the more advanced cylinder heads you’ll find in high-end cars. And if you might think that cast aluminum covers are lighter than stamped steel, we’re here to tell you that they are heavier because of their thickness.
Perhaps the most expensive of the four, billet covers offer far more superior traits for both function and looks. Billet valve covers start out as a solid block of metal that is machined down to achieve the desired shape and design. Their construction method, unlike casting, involves removing excess materials from the metal block called a billet.
Can you drive with a damaged valve cover?
The valve cover’s purpose goes way beyond protecting or covering the top of the engine. It seals in oil so that the engine won’t overheat due to low oil levels. A valve cover that’s loose or cracked will not be able to fulfill its duty properly and may cause your engine to either overheat or gradually wear down its parts.
Overheating happens when there’s not enough oil to lubricate the moving parts inside the engine. As you already know, there’s friction involved when the metal parts in your engine begin to move. To eliminate the effect of friction that can wear the parts down quickly, oil needs to circulate in and out of the engine. That means driving with a leaking valve cover and letting your oil deplete is a big no-no, as you’ll be facing more expensive engine repairs.
When to replace the valve cover
Leaking valve covers will eventually lead to major engine problems, which means you should address issues immediately after noticing them. Among the symptoms you need to take note of are:
- The engine is running rough
- Noticeable power loss
- Burning oil odor
- Gunk buildup on top of the cover
- Oil puddles underneath your vehicle
Since these symptoms can be caused by another faulty component, you’ll have to rule them out by diagnosing which component is causing the leak. This can be done through visual inspection although you’ll need special tools to access electronic components, such as sensors. If you don’t have the necessary tools, bringing your car to a certified mechanic is your most viable option.
Things to Consider When Buying a Valve Cover
Address a faulty valve cover right away before it causes more serious and costly damage to your engine. Here are a few things to keep in mind while choosing a replacement valve cover.
A lot of brands in the market today offer the valve cover in a variety of finishes that you can choose from. The most popular finishes out there are black, powdercoated, and chrome.
Black is ideal because this color makes it easier to detect dirt. A powdercoated finish gives the cover a matte texture that looks very classy. Lastly, the chrome variety is bright and shiny, so your ride will definitely look good on the road. Depending on what type of look you want for your car, you should choose one according to your preference.
The valve cover is typically made of one of three materials: aluminum, cast aluminum, and steel. All three are made to last and withstand the harshest road conditions. Just remember to buy from a brand with a reputation that you can trust to get the best valve cover for your ride.
How much is an OE valve cover replacement?
You can save money by purchasing original equipment or OE valve cover replacements on CarParts.com, with options as low as $18. Meanwhile, higher-quality valve covers can cost around $300 to $760. These are sold individually, in sets of two, or as part of a kit including valve cover gaskets.
Aside from the price range, you may filter the result by selecting which material you favor the most. There are options for aluminum, cast aluminum, die-cast aluminum, steel, plastic, and stamped steel valve covers that feature either universal or direct product fit.
Speaking of filtering, you may find the perfect part for your specific vehicle by typing its year, make, and model in the filter tab under the search bar. This will narrow down the results to parts that are compatible with your vehicle. You can then customize it further by choosing which brand, price range, and part series you prefer.
Valve cover installation
The valve cover is the component that provides your engine's head and valves the protection that they need. Overtime, this cover tends to develop rust, and this is due to the extreme amount of moisture and heat that it gets exposed to on a daily basis. To address the problem, get a good replacement for your old and worn-out valve cover right away. Below are some basic steps that you can follow to fix your vehicle's problem part.
Difficulty Level: Moderate
Parts and tools to prepare:
- Thread tap
- Socket and ratchet
- Metric wrench set
- New valve cover
Step 1: To remove your current valve cover, pull out the PCV valve that's on top of it. After that, use your socket and ratchet to unbolt the cover from the engine head.
Step 2: Once all the bolts or screws have been removed, pull the cover off of your engine head. For this step, be very careful about getting your engine head contaminated by the peeled gasket.
Step 3: To start your installation, dry fit your new valve cover on the engine head to ensure that all the holes are lined up correctly. If you find that some holes in the cover have no corresponding threads, note them using the marker pen, and tap them using the thread tap. Likewise, if you find some engine heads that have no corresponding holes, mark these spots to make it easier to locate them. After that, drill and tap them using a drill and thread tap, respectively.
Note: Drill and tap holes with utmost care to avoid metal shavings from entering your engine's oil return holes. To make your job easier, you can put a doughnut-shaped magnet around the hole every time you drill.
Step 4: Before you install your new valve cover, clean your mounting surface. Also, apply a thin layer of gasket sealant to secure the gasket's attachment. Aside from making your installation easy, doing this will also maintain the proper alignment of your components for a long time.
Step 5: Attach your new valve cover by loosely installing all the screws and bolts that come with it. Start from the middle part of the valve and slowly make your way to the sides. Make sure you tighten all the mounting hardware according to their specific torque specs. Do not overdo it because it can crack if not handled with care.
Step 6: To test your new cover, start your engine and watch out for leaks.
Tips and Warnings:
When drilling your assembly, make sure you don't drill too deep because this can result to damage in the water jacket.