Symptoms of Valve Cover Gasket Leak: Causes and How to Fix ?

When it comes to sealing an engine from oil leaks, the gasket is a vital component that prevents oil leaks, but it has not been given any recognition from most car owners. The valve cover gasket serves as a shield that helps to keep your engine oil from leaving your car in-between the head cylinder and the valve cover itself.

Although the valve cover gasket is shielded from both up and downsides, it is very delicate and prone to damage from the sides since it is manufactured with plastic and rubber. Over time, the gasket becomes brittle and dries up or crack due to exposure to heat. When this happens, the gasket will lose its value, causing severe issues like low engine performance and oil leaks. To prevent these issues, you have to know the Symptoms of valve cover gasket leak.

What is valve cover gasket?

Valve cover gasket is one of the most important gaskets in the engine that prevents your valve cover from oil leaks. It is placed in between your valve cover and the cylinder heads. Valve covers are made of rubbers or plastics.

valve cover gasket leak repair cost

As we all know, the oil pump sends pressurized oil to the head cylinder to enable adequate lubrication to the valves and the mechanism that drives them. As the oil pump sends the oil to the cylinder head, oil clings to the surface of the valve cover, and this oil will escape if there are any little openings.

In most cars, tiny bolts are used to fasten the valve cover together with the cylinder head. Without the valve cover gasket, there will be a tremendous amount of oil leaks.

Valve Cover Gasket Leak symptoms

There many valve cover gasket leak symptoms that will pop up once you have a gasket leak. If you notice any of the following symptoms, be prepared to diagnose the valve cover gasket leak and fix it with the step-by-step guides below or contact your mechanic as soon as possible to check and replace your bad valve cover gasket.

Burning Oil Smell:

When a valve cover gasket worn out, cracked, or pinched, oil from the cylinder head and beneath the valve cover finds a way to escape. When this happens while your engine is idling, the escaped oil that finds its way out through the leaking valve cover gasket will drip on engine parts like fuel intake, cylinder head, and sometimes, on exhaust manifolds or pipes. These components are all hot engine components that will burn the oil and generate a burning oil smell that an average car driver can easily recognize. If you perceive a burning oil smell, you have to diagnose your car for oil leaks or contact your mechanic to diagnose and fix the issue.

Low Engine Oil:

You should be aware that a bad valve cover cause vacuum leak. As engine oil escapes through a leaking valve cover gasket, it gets out of the oil pan. If such a situation occurs for a long time, it can cause an engine oil light to appear on your dash, which indicates low oil in the engine. If the engine oil is low, it will undoubtedly reduce its value from adequately lubricating internal engine components; this occurrence will generate excess heat inside the engine and cause friction between moving engine parts. If you see an engine oil light on your dash while idling or driving, you have to check your oil level – If it’s low, you have to inspect for oil leaks or contact your mechanic for a professional diagnosis.

Engine Rough Idling or Misfire:

If you have ever asked, can a leaking valve cover gasket cause rough idling? Yes. In some car models and makes, the valve cover serves as a seal that prevents oil from getting into the spark plug tubes. Most of these gaskets are designed in the form of O-rings. So, when your gasket shrinks due to the high temperature in the engine, it allows oil to seep inside the spark plug tubes. Can a bad valve cover gasket cause a check engine light? Absolutely! When engine oil seeps inside the spark plug tubes, it reduces the engine performance and causes a misfire.

Dirty and Greasy Valve Cover:

During oil change or some other work on your engine bay, most technicians inspect oil leaks around valve covers and other surrounding components. The most typical indication of when the valve cover is dirty and Greasy or fresh oil coming from it. When oil leaks out from the valve cover gasket, it will mix with dirt and debris, which will make it appear greasy on the cylinder head or valve cover. If you look under your hood with under hood work light during an oil change or other maintenance and notice grease or oil near your head cylinder, it’s most likely that your valve cover leaks.

How to Fix Valve Cover Leak – step by step guides

A leaking valve cover gasket can cause you a lot if you don’t fix it. Don’t worry. I’ll explain how to fix a valve cover gasket leak in simple terms. That said, let’s quickly look at the valve cover gasket quick-fix method.

valve cover gasket leak quick fix

Tools Needed:

  • Flathead screwdriver clean rag
  • Wrenches or socket set
  • Smooth sandpaper or gasket scraper
  • A clean rag.

Pasts Needed:

  • Gasket sealant
  • New gasket.

Step 1: Park your car

Park your car on a level, hard ground, and engage your hand brakes.

Step 2: Allow the engine to cool.

Open the hood and wait for the engine to cool so it won’t burn your hand.

Step 3: Unplug/disconnect the connection.

Unplug the ignition coil wires by depressing the lock tabs and pulling out the ignition coil’s wire socket.

Step 4: Unbolt the fastening bolts.

Use proper mechanic tools like ratchets and wrench sockets to Unbolt the ignition coil fastening bolts.

Step 5: Take off the ignition coils

Gently take off the ignition coil by pulling them off the valve cover.

Note: you may have to slightly twist the coil to pull it off if it’s proving stubborn to come out.

Step 6: Unbolt the valve cover fastening bolts

Use appropriate mechanic tools like wrench sockets to  Unbolt all the valve cover fastening bolts.

Step 7: Gently pull off the valve cover

Pull off the valve cover from the head cylinder by slightly shaking the valve cover sideways or use a flat screwdriver to pry it off.

Step 8:  Clean the valve cover

Use your gasket scraper and clean the valve cover, ensure you remove any gasket debris on the surface. Clean the head cylinder and make there is no leftover gasket debris on it.

Spray your brake cleaner to keep the surface free from oil residue.

Step 9: Install the gasket on the valve cover.

Carefully install the spark plug seals and the new valve cover gasket and back on the valve cover.

Step 10: Apply instant sealant.

Add a slight instant sealant on the valve cover where it seals with the cylinder head.

Step 11: Mount the valve cover

Mount the valve cover on the head cylinder and drive the bolts with your hand until they catch the thread.

Step 12:  Tighten the valve cover bolts.

Tighten the valve cover bolts to the manufacturer’s specification with your torque wrench.

Step 13: Fix back the ignition coils to their position

Fix back to ignition coils back on the spark plug tubes just the same way you removed them.

  • Note: If there is oil contamination on the coils, you have to replace the coil boots.

Step 14: Tighten the Coil fastening bolts.

Place back the ignition coil fastening bolts and run them with your hand until they catch the thread, use your torque wrench and tighten the bolts to the manufacturer’s specifications.

Step 15: Reinstall the electrical wires

Plug back the spark plug sockets on the plugs by pressing them into the plug heads until you hear a locking sound.

 Step 16: Check the engine oil level

Gauge the oil level. If it’s below the standard gauge, add more oil.

Step 17: Start the car and inspect the valve cover.

Start your car and allow it to idle for some time. Check for any oil leaks in the valve cover.

FAQs

Q: Can you drive a car with valve cover leaks?

Yes, you can drive a car with a valve cover leaks in as much as the amount of oil leaks from the valve cover gasket is small, and the oil is not dripping on hot engine parts like the exhaust manifold or pipes. If this is the case, it is relatively safe to drive your car until you have a chance to visit a mechanic garage or fix it yourself.

Q: Is a valve cover gasket leak serious?

Is valve cover leak serious?  When the valve cover gasket shrinks over time due to the engine’s high temperature, the gasket will lose it’s value and leak, commonly causing oil leak issues, reduced engine performance, or drivability issues. If not fixed on time, a valve cover gasket leak can cause severe engine breakdown.

Q: When should a valve cover gasket be replaced?

Because the valve cover gasket is made of rubbers, under excess heat from the engine, and over time, the gasket tends to shrink and becomes brittle, which is the most common cause of oil leak around the valve cover. When should you replace it? The valve cover gasket does not have any maintenance requirements. It should only be it shrinks or leaks. However, the valve cover gasket is often replaced when doing major engine maintenance.

Q: How long can you drive with an oil leak?

It is always good to not run your car if it has an oil leak. However, a short distance drive within the city, less than 15 miles is not dangerous as driving with an oil leak until it lowers your oil level. In a nutshell, if the oil leak is much, do not drive the car at all.

Q: Can a valve cover gasket leak cause smoke?

As oil leaks from the valve cover gasket, the oil will end up running down till it gets on the exhaust manifold or pipes. As the engine gets hot while idling or running the car, the exhaust will get hot and the oil. As soon as this happens, you’ll see white smoke coming from under your hood.

Final word

Whether the first symptoms of valve cover gasket leak you noticed is an ignition misfire, puddle of oil on the floor, the smell of burning oil, or low engine oil level, you have to replace the valve cover gasket once you find out that it’s leaking.

In some rear cases, it could be that the valve cover is not well-tighten, so tightening it may stop the leak. But typically, once the oil starts dripping out, you need to loosen the valve cover and add instant sealant to the gasket or replace it if it’s long gone. Fixing small oil leaks before it gets spread over other components can help you diagnose other future oil leaks on your engine.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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