With all the recent innovations in automotive technology, it’s sometimes hard to keep track of all the new features manufacturers add to engines every year. However, some important parts stayed mostly the same for the last couple of decades. The valve cover gasket is one of them. The fact that it hasn’t been constantly improved with techy bells and whistles makes it easy to forget what it does and what happens when it becomes faulty. To help you understand how important valve cover gaskets are, here’s an article explaining what valve cover gaskets do, how to identify the faulty ones as well as how to replace one by yourself and save money at the same time.
What is a valve cover gasket?
A valve cover gasket is a component making sure that the engine oil contained in the engine head and valvetrain doesn’t spill out of the valve cover while the engine is running. It’s usually a simple rubber gasket placed in a specifically-designed groove around the valve cover and sitting tightly between the cover and the engine head. Every car ever made has one and they pretty much all look the same.
Other types of gaskets
Certain vehicles are equipped with gaskets made of cork instead. While cork is more durable than rubber, cork gaskets are mostly found on older American-made engines. Luxury and more expensive sports cars may also have valve cover gaskets made of laminated cork which is basically a metal gasket looking a lot like head gaskets but covered in cork on both sides. On recent vehicles, you may find composite valve cover gaskets instead. These are, by far, the most durable ones which would explain why tuners frequently replace their factory gaskets with composite ones.
However, rubber is still the most widely used type of gaskets, mainly because of the low manufacturing cost and relative reliability. Don’t forget that car manufacturers rarely work with your wallet in mind and using components with a limited lifespan is often more profitable for them.
How to know if your car’s valve cover gasket needs to be replaced
The answer to that question is quite simple. You only need to replace a valve cover gasket once it starts leaking. A quick visual inspection should be more than enough to find out if your valve cover gasket is leaking or not. Look around the engine head, right where the valve cover meets the head and look for oil deposits.
When a valve cover gasket starts to leak, it will do so gradually. At first, you’ll be able to notice something like a greasy film around the valve cover. After a while, the leak will increase and the outside walls of the engine head will look wet and greasy. If a crack occurs in the gasket, you’ll be able to see engine oil dripping from the cover. In the worst-case scenario, you could even find a small puddle of oil on the bell housing of the transmission and the floor under the engine bay.
Valve cover gaskets tend to leak frequently around the same areas, in particular near the camshaft grommets on the opposite side of the timing belt. It’s not uncommon to see oil infiltrate the spark plug tubes too. The seals preventing oil from entering the spark plug tubes are usually separate components from the valve cover gasket but since they come in the same kit, you might as well change the gasket and all the seals while you are there.
Faulty valve cover gasket symptoms
As opposed to most other car problems, a leaking valve cover gasket won’t make any unusual sound or lead the engine to behave erratically. In fact, an engine would work just fine even if you were to completely remove the gasket altogether. Engine oil would leak everywhere but the engine would still be running alright. That’s why regular inspections are so important.
At the very worse, if your valve cover gasket leaks like crazy, you might detect a strong burned oil smell if oil is leaking on a hot component like the exhaust system. You could also notice small dark spots under the car when leaving in the morning. If the leak is important enough, the low oil level warning light may come up at some point but only if the oil level reaches a certain threshold.
If oil is leaking into the spark plug tubes, however, it might cause intermittent misfires but only if the oil can reaches where the coil-on-plug connects with the plug (or the rubber section of the spark plug wires if your car is kind of old).
Average valve cover gasket replacement cost
The cost of replacing the valve cover gasket on your car depends on 2 factors: your car model and who’s going to do the repair.
Car model matters
The kind of car you drive comes first. The cost of a valve cover gasket is obviously not the same for a Porsche than for a Hyundai. The engine configuration also has an impact on the total cost or the repair. A V8 will need 2 different valve cover gaskets while an inline 4 will only need one. A valve cover gasket on a flat-four like Subaru Boxer engines is also a lot more complicated to replace and takes a lot more time because of the reduced space and the valve covers being on a vertical axis instead of being placed horizontally like most other cars. The same thing happens with a rear-engine vehicle. Have you ever tried doing any kind of engine work on a Toyota MR2? If yes, you’ll know what I’m talking about!
Replacing a valve cover on an inline-four engine like a Hyundai Accent or Toyota Yaris takes about an hour or so. Double that for a V engine as two gaskets take twice the same amount of time. Double that again for a Boxer or rear-engine configuration.
Dealer vs. Repair shop
Who’s going to do the repair also has a big impact on the total price tag. Car dealers are always more expensive than independent auto repair shops. And auto repair shops are always more expensive than DIY repairs, taking into account that you know what you are doing. Car dealers can charge anywhere between $80 and $150/hour these days while an independent auto repair shop might charge only half that amount.
All in all, if you own a 2015 1.8L Honda Civic, an aftermarket valve cover gasket kit including the spark plug tube seals would cost around $30+tx plus about an hour of work and maybe $10 in shop material like silicone gasket maker and brake cleaner. If your mechanic charges $80/hour, the total bill should be around $120+tx. If you own a 2015 3.8L Porsche 911 Carrera S, however, you’ll see that the cost of the gasket itself is relatively the same but the labor cost would be a lot more expensive.
Luxury car dealers
Porsche dealers often charge over $130/hour and may charge even more if you live in a big city. Porsche dealers in West Palm Beach, Florida are known to charge well over $200/hr. Since replacing both gaskets may take over 4 hours of labor, you may have to bank over $1,000 to have your valve cover gaskets replaced at a Porsche dealer.
Needless to say, the cheapest way to save on your valve cover gasket replacement is to do the work yourself. That way, no matter if you drive a Civic or a 911 Carrera S, the cost of the replacement would only come down to the tag price of the gasket. Be careful, though. Attempting to perform a job you don’t have the qualification or knowledge to do correctly might end up being more expensive in the long run. Only try to replace your valve cover gasket if you have some basic auto mechanic skills and make sure to get your hands on your car’s repair manual first. Just in case you need to refresh your memory a bit and make sure you don’t forget anything important along the way.
How dangerous is driving your car with a leaking valve cover gasket?
Even though your car can still work just fine with a leaking valve cover gasket, it doesn’t mean that you should leave it like that. In addition to smelling bad when burning on hot components, oil can damage seals and various sensors installed on the engine.
Even worse, if enough oil drips on the flex pipe of your exhaust, it can infiltrate the mesh and will keep on producing smoke and a bad smell even once the gasket has been replaced and you’ll need to replace the flex pipe to get rid of it.
Furthermore, burning oil is bad for your health. Oil releases harmful chemicals like carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, mercury, arsenic, and benzene when burning. Driving your car with a leaking valve cover gasket may not be that dangerous for your car or engine but it sure is for you.
How to replace a valve cover gasket
The first thing to do when replacing a valve cover gasket is obviously to remove the valve cover. To do that, you’ll need to take out everything that holding onto it. That means wire harnesses, PCV hose, coil-on-plugs; everything that’s hooked on the cover must go.
Remove the screws holding down the valve cover and pull it out. The cover might stay stick around the camshaft seal if there’s still some liquid gasket maker. To remove it, use a metal scraper and pry the cover out.
Do it right, do it once!
To make sure the new gasket sits correctly against the head’s surface, use brake cleaner and a razor blade to clean any silicone gasket left. Once it’s done, remove the rubber gasket from the cover and install the new one back into the groove.
Since rubber valve cover gaskets tend to leak around the camshaft seals, a neat trick is to put a thin layer of silicone gasket maker where the valve cover gasket meets the cam seal. Then, re-install the valve cover in its original position and tighten back the screws. Re-install the PCV hose and coil-on plugs and that’s it!
When should you replace your valve cover gasket
Valve cover gaskets should be replaced as soon as a leak is detected. In addition, they should also be replaced every time the valve cover is removed for any other reason. Multiple other repair jobs require to have the valve cover removed, like replacing the head gasket as well as any kind of work on the timing belt side for example. On the majority of cars, the timing belt cover is positioned under the valve cover so any work requiring the removal of the timing belt cover will also require the removal of the valve cover.
When the valve cover is tightened on a new gasket, the gasket will be pinched and squeezed tightly in place. Failing to change the gasket after removing the valve cover and re-using the same one will greatly increase the risk of leakage in the very near future and you’ll have to re-do the job all over again. Valve cover gaskets are quite inexpensive, especially if there’s no additional labor cost since the valve cover is already removed. You are better to just play it safe and replace it while you’re there.
To wrap it up
Whenever the valve cover gasket on your vehicle starts to leak, there’s no need to panic. After all, a leaking gasket will no cause your car to stall or result in any damage to your engine. It’s also a fairly simple job and its part of the regular maintenance every car owner will have to take care of at some point in the life of his car.
The real trick, if you can’t do the job yourself, is to find a certified auto mechanic you can trust and let him handle it. If you are lucky enough to have basic auto mechanic knowledge, you should be more than capable of replacing it yourself, especially since this is a job that can be done without having access to a hoist and only requires basic tools. When in doubt, check out the recommended valve cover gasket replacement procedure into your car’s repair manual beforehand and you should be good to go!