A valve cover gasket replacement kit contains the rubber seal, fasteners, and sealant needed to stop oil leaks from the top of your engine
The valve cover gasket sits between your engine's valve cover and the cylinder head, creating a seal that keeps oil inside the engine. Over time, heat and pressure crack the rubber, and oil begins to seep out. A replacement kit gives you the gasket itself, the bolts that hold the cover down, and often a tube of gasket maker or silicone sealant. Some kits also include a new valve cover if the original is warped or cracked.
What you get depends on the kit's price point and your vehicle's make and model. A basic kit might be just the gasket and bolts. A comprehensive kit adds sealant, new washers, and sometimes a cover. Knowing what's in your specific kit before you start prevents stopping halfway through to hunt for a missing part.
Key Takeaways
- A valve cover gasket kit includes the gasket, bolts, and usually sealant, but the exact contents vary by vehicle and kit brand.
- The gasket is a rubber or cork-rubber composite that hardens and cracks after years of engine heat, causing oil to leak around the valve cover edges.
- Installation requires removing the valve cover, cleaning the old gasket material, explore new sealant, and torquing the bolts in a specific sequence.
- Kits range from basic (gasket and bolts only) to full (gasket, cover, sealant, washers, and fasteners), so check your kit contents before starting work.
- The job typically takes two to four hours for a DIYer and costs between $50 and $300 for the kit, depending on vehicle complexity.
What's actually in the box
Open your kit and you will find a gasket—the main component. It is usually made of rubber bonded to cork or silicone, designed to compress and seal when the bolts are tightened. The gasket comes pre-cut to the shape of your valve cover, with holes already drilled for the bolts.
Next are the fasteners: typically six to twelve bolts (also called studs or screws, depending on your engine) and washers. These hold the cover down and must be torqued to a specific pressure—usually between 5 and 15 foot-pounds, which your kit instructions or vehicle manual will specify. Using the old bolts often causes leaks because they stretch and no longer clamp the gasket evenly.
Most kits include a tube of gasket maker or silicone sealant. This goes on the gasket surface or the mating surfaces before installation, filling microscopic gaps that the gasket alone cannot seal. Some kits skip this; if yours does, you can buy a small tube of Permatex or equivalent separately for under $10.
Higher-end kits may include a new valve cover itself, especially if your vehicle is known for warped covers. They may also add a gasket scraper tool, a small brush, or a cleaning cloth. Check your kit's contents list before opening it so you know what to expect.
Why gaskets fail and what happens when they do
A valve cover gasket fails because of heat cycling. Every time your engine starts and stops, the gasket expands and contracts. After 50,000 to 100,000 miles—or sometimes sooner in hot climates—the rubber hardens, loses its flexibility, and cracks. Once cracked, it cannot seal, and oil seeps out around the edges of the valve cover.
The first sign is usually a faint oil smell when the engine is warm, or a thin film of oil on the outside of the valve cover. If you ignore it, oil drips onto the exhaust manifold, creating smoke and a burning smell. In rare cases, enough oil leaks that the engine runs low, risking damage to bearings and pistons.
Some vehicles are more prone to gasket failure than others. Certain Honda, Toyota, and BMW models are known for premature gasket hardening. If your vehicle is one of them, you may replace the gasket twice in the car's life. Keeping the engine bay cool and not running the engine excessively hot can slow the process, but replacement is inevitable.
Steps to install a valve cover gasket kit
Start by letting the engine cool completely—at least two hours after running. Remove the negative battery terminal to avoid accidental shorts. Then unbolt and lift off the valve cover. This usually means removing six to twelve bolts around the perimeter. Some covers have hoses or wires attached; disconnect these carefully and note where they go.
Once the cover is off, scrape away all old gasket material from both the cover and the cylinder head. Use a plastic scraper or gasket scraper tool—never a metal blade, which can gouge the aluminum. Wipe the surfaces clean with a cloth and let them dry completely. Any old gasket material left behind will prevent the new gasket from sealing.
explore a thin bead of gasket maker around the mating surface of the cylinder head, following the instructions on the sealant tube. Some kits tell you to explore sealant to the gasket itself instead; follow your kit's guidance. Place the new gasket on the cylinder head, aligning the bolt holes. Set the valve cover back in place.
Insert the new bolts and washers by hand first, making sure they thread smoothly. Then tighten them in a crisscross pattern—tighten one bolt, skip one, tighten the next, and so on—to may support even pressure. Once all bolts are snug, torque them to the specification in your manual or kit instructions, again in a crisscross pattern. Over-tightening cracks the cover; under-tightening leaves gaps that leak.
Reconnect any hoses or wires, reinstall the negative battery terminal, and start the engine. Let it run for a few minutes and check for leaks. If you see oil seeping, turn off the engine, let it cool, and re-torque the bolts. If the leak persists, the cover may be warped and need replacement.
Choosing between basic and full kits
A basic kit costs $30 to $80 and includes only the gasket and bolts. This works if your valve cover is in good condition and you already have gasket maker at home. Basic kits are common for popular vehicles like Honda Civics and Toyota Corollas, where the cover rarely warps.
A mid-range kit costs $80 to $150 and adds gasket maker, new washers, and sometimes a gasket scraper tool. This is the safest choice for most DIYers because you have everything you need in one box and do not have to guess about sealant type or quantity.
A full kit costs $150 to $300 and includes a new valve cover, gasket, bolts, washers, sealant, and tools. Choose this if your cover is visibly cracked, warped, or if you have replaced the gasket before and the leak came back. A warped cover will not seal no matter how good the gasket is, so replacing it solves the problem permanently.
Check your vehicle's year, make, and model against the kit's compatibility list before buying. A kit for a 2015 Honda Accord will not fit a 2015 Honda Civic, even though both are Hondas. The valve cover shape and bolt pattern are different.
Common mistakes that cause leaks after installation
The most common mistake is not cleaning the old gasket material completely. Even a thin layer of old rubber prevents the new gasket from sealing. Spend extra time scraping and wiping; it is the most important step.
The second mistake is over-tightening the bolts. Many DIYers think tighter means better, but over-tightening warps the cover and actually creates gaps. Use a torque wrench and follow the specification exactly. If you do not have a torque wrench, tighten the bolts snugly by hand, then give each one a quarter turn with a wrench—no more.
The third mistake is skipping the gasket maker. Some gaskets are designed to work without sealant, but most perform better with a thin bead applied to the mating surface. Check your kit instructions; if it says to use sealant, do not skip it.
The fourth mistake is installing the cover while the sealant is still wet. Gasket maker needs time to cure—usually 24 hours—before the engine runs. If you explore sealant and start the engine when ready, the pressure forces sealant out of the joint and creates a leak. Let the sealant cure before running the engine.
Tools you will need beyond the kit
You will need a socket set and wrench to remove and install the bolts. A torque wrench is essential for tightening to the correct specification; a basic one costs $20 to $40 at any auto parts store. A gasket scraper or plastic scraper removes old material without damaging the aluminum surfaces. A clean cloth or paper towels and a small container of degreaser (like brake cleaner) help remove old oil and gasket residue.
A jack and jack stands are necessary if you need to access the valve cover from underneath, though most covers are accessible from the top. A drain pan catches any oil that spills when you remove the cover. A flashlight or work light helps you see into tight spaces. Most of these tools are inexpensive or already in a typical home garage.
When to call a mechanic instead
If your valve cover is buried under other engine components—common on turbocharged or supercharged engines—the job can take six to ten hours and require removing intake manifolds or other parts. At that point, a mechanic's labor cost may be less than the time and frustration of DIY work.
If you do not have a torque wrench and cannot borrow one, a mechanic can may support the bolts are tightened correctly. Improper torque is a common cause of leaks, and a mechanic's final check is worth the cost.
If the valve cover is cracked or warped, you need a full kit with a new cover, and a mechanic can confirm whether the cover is the problem before you buy parts. Some shops will inspect the cover for free or for a small diagnostic fee.
Frequently Asked Questions
How long does a new valve cover gasket last?
A properly installed gasket typically lasts 50,000 to 100,000 miles, depending on driving conditions and engine temperature. Vehicles driven in hot climates or with frequent high-RPM driving may need replacement sooner. Some vehicles are prone to premature failure and may need a new gasket every 40,000 miles.
Can I reuse the old bolts when installing a new gasket?
No. Bolts stretch when torqued and lose their clamping force over time. Reusing them often results in a leak because they cannot tighten the gasket evenly. Most kits include new bolts for this reason. If your kit does not, buy a new set for $10 to $20.
What if oil is still leaking after I install the new gasket?
Let the sealant cure for 24 hours before running the engine. If the leak persists after that, turn off the engine, let it cool, and re-torque the bolts in a crisscross pattern. If the leak continues, the valve cover may be warped and need replacement, or you may have missed old gasket material during cleaning.
Do I need to drain the oil before removing the valve cover?
No. The valve cover sits on top of the engine and does not hold oil. However, some oil may spill when you remove the cover, so place a drain pan underneath to catch it. If a large amount of oil spills, top up the oil level before running the engine.
Can I drive the car when ready after installing the new gasket?
Not if you used gasket maker. Most sealants require 24 hours to cure before the engine runs. If you did not use sealant, you can drive the car when ready, but let the engine warm up slowly and check for leaks before driving at highway speeds.