6 Bad Valve Cover Gasket Symptoms and Replacement Cost

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valve cover gasket leak symptoms

When a car ages, its engine goes through various stages of wear and tear. One aspect that disproportionately affects vehicles is the gaskets in their components. They can eventually fail due to friction or constant exposure to heat, making them more complicated over time, causing leaks and further damage with every drive you take!

Whenever it comes to engine sealing, these gaskets are indeed the unsung heroes that take a lot of damage but are seldom acknowledged for it. This valve cover gasket is among the most critical gaskets to protect your cylinder head components against the elements and prevent oil from leaking the engine.

Most valve cover gaskets are composed of cork or plastic and serve to seal your valve cover and cylinder head. While a valve cover gasket is effectively secured from both top and bottom, it’s pretty sensitive and prone to side damage.

This gasket gets brittle and cracks caused by exposure to debris, dirt, temperature, and other substances over time. The valve cover gasket may lose its quality and leak when this happens, resulting in visual concerns such as oil leaks, drivability, and engine performance difficulties. A bad valve cover gasket, if not changed promptly, may result in serious engine damage.

In this article, we’ll be discussing a few frequent bad valve cover gasket symptoms that signal a possible issue. If you notice any of these signals, take your car for servicing immediately to have the valve cover gasket replaced if necessary. Read on to learn more!

Bad Valve Cover Gasket Symptoms

  • Dirty Valve Cover and Visible Oil Leak
  • Low Engine Oil Level
  • Burning Oil Smell
  • Engine Misfire and Rough Idling
  • Dashboard Warning Lights
  • Smoke Coming from the Engine

Valve Cover Gasket And Its Function

A cylinder block topped by a specific bank of cylinders is the main feature of an internal combustion engine. A cylinder head is located above the cylinder banks and aids in the engine’s combustion process. The channels inside the cylinder head enable air and fuel into the cylinders.

On top of the cylinder head is a component known as the valve cover; it’s often constructed of plastic or metal. Another piece, referred to as the valve cover gasket, is located between the valve cover and cylinder head. The valve cover gasket acts as their surface sealant between these two components.

Meanwhile, this gasket retains the oil within the vehicle’s engine, ensuring that it continues to circulate and lubricate the engine’s numerous components. Depending on the configuration of your engine, you might have one or two valve cover gaskets.

Valve cover gaskets are often manufactured from molded silicone rubber and are designed to fit snugly around your valve cover. Since rubber isn’t the most durable material available, it will eventually wear out and develop cracks.

Once this occurs, the oil will seep out of your engine, reducing the ability of the engine’s components to be lubricated. Valve cover gaskets on older cars were often made of cork, copper, or a mix of these materials. These have their drawbacks, so manufacturers are shifting their focus to rubber for current automobiles.

Leaking Valve Cover Gasket Symptoms

When you first detect a leaking valve cover, there’s still time to address the issue before it worsens. Below are the typical valve cover gasket leak symptoms that can assist you in determining the source of its leak.

Dirty Valve Cover and Visible Oil Leaks

Most vehicle mechanics will examine your valve cover when doing an oil change. The valve check is performed to see any leak emanating from your valve cover gasket. The most obvious “red flag” for auto mechanics is if your valve cover head is clogged with debris.

It is well accepted that engine oil gathers particles and filth behind the hood. Additionally, this material will accumulate to the point where it becomes “caked” and heaped upon your valve cover or cylinder head.

Therefore, if you go beneath your hood and notice that your valves are greasy, there is a significant probability that you have a leaky valve cover and requires a new valve cover gasket.

Low Engine Oil Level

You should be aware that a defective valve cover would result in an engine oil leak. Engine oil leaks out of your oil pan due to a failing valve cover gasket.

If this scenario persists for an extended period, your engine oil light will illuminate on your dashboard, indicating that the engine is running short on oil.

Once your engine oil level is low, it’ll surely lose value due to insufficient lubrication of internal engine components; it will produce excessive heat within your engine and increase friction among working engine components.

If you notice an engine oil light on the dashboard while running or idling, you must inspect your engine oil level. If it’s low, you must check for engine oil leaks or call your trusted mechanic for a thorough diagnostic.

Burning Oil Smell

Once a valve cover gasket becomes worn, brittle, or cracked, oil from your cylinder head and under the valve cover leaks.

If this occurs when your engine is idle, the leaking oil drips onto engine components such as its cylinder head, fuel intake, and occasionally, exhaust manifolds and exhaust pipes.

These are all hot engine components that would burn the leaking engine oil and emit an odor similar to a burning oil smell that an ordinary automobile driver can readily identify.

When you smell burnt oil, you must inspect your vehicle for oil leaks or hire a professional to locate and repair the problem.

Engine Misfire and Rough Idling

Whether you’ve ever wondered if a failing valve cover gasket might result in rough idling, the answer is yes.

The valve cover acts as a seal to keep oil from entering the spark plug tubing in specific vehicle make and models. The majority of such gaskets are shaped like O-rings.

As a result, engine oil seeps into the spark plug tubes when the gasket cracks due to the engine’s hot temperature.

It can also absolutely trigger your check engine light! Engine oil leaks into the spark plug tubes, resulting in reduced engine performance and misfire, and might also require a spark plug replacement.

Dashboard Warning Lights

If you haven’t been routinely changing your engine oil, the first indication that anything is incorrect could be dashboard warning lights.

Your Oil Warning Light may illuminate to indicate that there is insufficient oil pressure in your system, or it may illuminate the Check Engine Light due to flaws caused by a cracked gasket and valve cover.

In any case, these warning lights represent a significant problem, and you should avoid driving until the issue is repaired.

Smoke From Engine Compartment

Smoke might also emerge from your engine compartment in certain instances when engine oil leaking from your valve cover gasket leaks down the exhaust manifold and other hot engine parts.

What Causes Valve Cover Gasket Leaks?

Since valve cover gaskets are vulnerable to leaking over time, numerous distinct causes might contribute significantly to the deterioration of the structural quality of valve cover gaskets. The majority of these are at least partly related to vehicle maintenance.


Overheating is a primary reason for valve cover gasket leaks. Each vehicle’s engine is designed to run at a specific temperature.

When this predefined value is surpassed, such as when an engine overheats, any engine’s gaskets get heat strained, increasing the likelihood of breaking and bursting out.

Not only is excessive heat detrimental to your valve cover gasket, but it also endangers the durability of other critical seals, including your engine’s cylinder head gasket.

Several blown gaskets on an engine are not unusual in outrageous engine overheating.

Irregular Oil Change

Irregular engine servicing is probably the primary cause of earlier valve cover gasket breakdown. Engine oil that has been changed regularly has a variety of compounds that help prevent gasket damage.

Over time, these compounds degrade, exposing your engine’s valve cover gasket to increased wear and deterioration. This frequently happens when regular maintenance tasks are neglected for a long time.

Loose or Overtightened Valve Cover Bolts

Also, a recent valve cover gasket replacement often starts leaking shortly after installation if the engine’s valve cover bolts aren’t correctly torqued.

Excessive torque on valve cover bolts could result in incorrect gasket fitting or pinched gasket edges. Also, improper tightening of such bolts often precludes the formation of an adequate seal between your engine’s cylinder head and valve cover surfaces.

How to Fix Valve Cover Gasket Leak?

If you do not repair a leaky valve cover gasket, it might cause significant damage. Do not be concerned. We’ll discuss how to replace a leaking valve cover gasket if you possess a few mechanical skills and plan to DIY the task. Let’s briefly look at the fast-fix approach of your valve cover gasket replacement.

Step 1: Remove the Engine Cover

To begin, dismantle your engine cover. Numerous engines use full-coverage plastic tops. Its plastic engine cover should be uninstalled to provide complete access to your valve cover.

Step 2: Uninstall the Components

Continue with the component removal. A valve cover is usually accessible on a four-cylinder engine once all electrical components and emission control tubes are uninstalled. There might be any accelerator connections that are obstructed, in which case you’ll have to loosen them.

You may or may not remove the air intake manifold from a six- or eight-cylinder engine. This component would need to be removed depending on which valve cover gasket is leaking.

Step 3: Remove the Bolts and the Valve Cover

After gaining access to your valve cover, unscrew valve cover nuts or bolts and take your valve cover. The sealing surface of your valve cover will next be tested using a straight edge to ensure that it is flat, usable, and secure.

Step 4: Clean the Valve Cover

Clean your valve cover using a gasket scraper, ensuring that any gasket dirt on the surface is removed. Tidy your head cylinder thoroughly and check for any remaining gasket debris. Spray a brake cleaner on the surface to make it clean and free of oil residue.

Step 5: Gasket Installation

Time to install your replacement gasket. Your new valve cover gasket and any necessary rubber grommets shall be installed. If any spark plug tube seals require replacement, these should be replaced as well.

In certain instances, you might apply oil-resistant vulcanization or an RTV sealant to different portions of the sealing surface to provide secure, efficient, and airtight sealing.

Next, place and secure the valve cover. It would be great if you utilized a calibrated inch-pound torque wrench to measure the tightness of the bolts correctly. Then reinstall all remaining components in their appropriate locations.

Step 6: Test

After the setup is finished, test-run your engine and check for leaks.

Valve Cover Gasket Lifespan

The lifespan of a valve cover gasket is highly dependent on many circumstances. These considerations include the engine’s manufacturer, the driver’s driving patterns, and the schedule of routine maintenance.

Specific aftermarket gaskets are built to be more robust than others, resulting in a lengthier lifespan. Also, valve cover gaskets in a properly maintained vehicle are nearly always more durable than those in a mismanaged one.

Furthermore, gaskets in a car’s rarely driven engine are more vulnerable to early failure since they grow hard and dry.

But, on average, people could anticipate their engine’s valve cover gaskets to survive between 50,000 up to 80,000 miles without incident. In certain circumstances, these types of gaskets could last far longer.

Things To Keep In Mind After Valve Cover Gasket Replacement

Below are the following points that would be best to consider when replacing your leaking valve cover gasket.

Some Gaskets are Easy to Change

Mechanical parts of a car engine often outlast the gaskets utilized to seal your engine. Numerous gaskets, including the valve cover gasket, are pretty simple to change.

No to “Stop Leak” Products

Avoid any “stop leak” products regarding your engine oil that you might come across. They may seem beneficial in principle, but they often cause more trouble than they’re worth.

Most of these chemical solutions are not even defined or permitted by car manufacturers. Therefore, leave them alone since they tend to develop more issues while increasing the cost of repairs.

Leak Test

Often, more leaks are almost inevitable if a car is old enough to suffer a valve cover oil leak. As a result, it’ll benefit you to request a leak examination from your trusted mechanic. What’s the point of repairing a leak if other leaks exist?

Inspect Other Rubber Components

Occasionally, your Positive Crankcase Ventilation valve, or PCV valve, is put into a rubber grommet located in one of your valve covers.

You might have a leaking point with an old and fractured rubber grommet. Once you get access to your valve cover, check those components and repair them as necessary.

Can You Drive A Car With A Valve Cover Leak?

Driving a car suffering from a valve cover leak that spills just a little quantity of oil or oil that drips down your driveway instead than into hot engine components is safe to drive in the short term.

While running with any oil leak isn’t encouraged, it is acceptable if no other means of transportation are available. The valve cover gasket might sometimes leak enough oil to drop over your scorching exhaust manifold.

A burning oil smell or whitish smoke from the exhaust indicates a significant leak. In this scenario, do not drive your automobile until your leaking valve cover gasket has been repaired.

However, when you are forced to drive your automobile with a leaking valve cover gasket, you must be mindful of the accompanying short-term engine impacts.

Oil Leaks Can Impact Engine Performance

A leak in the oil system affects the engine’s performance. Engine oil is employed to lubricate moving components such as your pistons. During steep climbs, you might need to shift up a gear to adjust for the loss of power. This could be difficult if you need to shift into lower gears along with steep climbs, such as when driving out into the freeway.

Oil Is Important To Protect Your Engine

Engine oil is also critical in preventing rust in your engine. When driving over stagnant water during rainfall, metal components might corrode and seize altogether if there’s no oil left or enough oil to protect them.

Valve Cover Gasket Replacement Cost

The typical cost of replacing a valve cover gasket is around $100 up to $350. The components will typically cost approximately $30 up to $50, whereas the labor would cost about $70 up to $300.

That said, some vehicles have valve cover gaskets that cost over $100, and labor expenses may be much more significant owing to a complicated engine setup.

However, this is a relatively inexpensive component to replace in most situations. The cost will be determined by your technician’s hourly rate and the quality and quantity of your components.

If you can find an experienced mechanic that charges a lesser hourly rate and works swiftly, you might save money on labor expenses.


You can continue driving even if your valve cover gasket is failing. However, you want to ensure that any oil leaks are small, and there should be no oil hits on any hot engine components.

As previously stated, oil on hot engine components may cause smoke and a burning oil smell. While your vehicle is drivable, this does not imply that you should disregard any issues and get it fixed soon.

When discovering a gasket leak, you might encounter low oil levels, check engine lights, and other issues. Thus, the more you postpone, the higher the likelihood of your car entirely failing.

While changing your valve cover gasket might seem to be a straightforward task, this gasket is frequently concealed behind many engine components.

Consequently, if you’re unfamiliar with engine configurations or have never replaced engine parts before, the task could quickly become tiresome.

These are the instances when you want to have the assistance of a skilled mechanic who can aid you in completing the task quickly. Finally, you could have peace of mind and not worry about the nitty-gritty details.


Can you drive a vehicle with a leaking valve cover?

Yes, you could drive a vehicle with a leaking valve cover as long as the quantity of oil leaking from your gasket is minimal and your oil is not spilling on hot engine components such as the exhaust manifold and pipes. If this is the situation, driving your automobile until you can see a repair shop or service it yourself is reasonably safe.

Is the valve cover gasket leak a cause for concern?

Is there a significant valve cover leak? When the valve cover gasket contracts over time due to the engine’s hot temperature, it loses its effectiveness and leaks, often resulting in oil leaks, decreased engine performance, and drivability issues. A leaking valve cover gasket, if not repaired promptly, might result in a major engine failure.

When is it necessary to replace a valve cover gasket?

Since your valve cover gasket is composed of rubber, it shrinks and gets brittle when exposed to excessive heat from your engine, which is the most typical cause of oil leakage under the valve cover. 

When is the right time to change my valve cover gasket? 

Your valve cover gasket requires no maintenance. It must only be a case of it contracting or leaking. However, while doing substantial engine repair, the valve cover gasket is mainly changed.

How long can you drive if you have a valve cover leak?

It is usually prudent to avoid using your vehicle if it has any oil leaks. A brief trip inside the city, or less than 10 miles, is not as harmful as driving with any oil leak until your oil level drops. If your oil leak is significant, avoid driving your automobile.

Can a leaking valve cover gasket result in smoke?

As oil seeps from your valve cover gasket, it runs down your exhaust manifold or exhaust pipes. The exhaust and oil get heated as your engine heats up while idling or driving. You will notice white smoke emanating from underneath your hood when this occurs.

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