Bad Valve Cover Gasket Cause Vacuum Leak – How Do I Fix It?

It is a common issue when a bad valve cover gasket cause vacuum leak within your car, but inexperienced drivers might have some trouble dealing with it.

The cover gasket is one of the most important parts of the engine; therefore, you should learn how to protect it properly.

Despite being covered from both upper and lower, most valve covers are only protected by weak materials like plastic or light rubber. Therefore, rough idles may happen while driving if this part is not regularly checked.

Let’s go into closer detail about the valve gasket’s structure and how to deal with a back valve cover gasket leak!

Can A Bad Valve Cover Gasket Cause Vacuum Leak?

Yes, sure!. A bad valve cover gasket will almost certainly lead to a vacuum leak. Prolonged pressure over time on the right angle can gradually harm it due to weak plastic or rubber wrap layers.

This will lead to severe oil leaks that dry up and form cracks from heat exposure.

There are many symptoms of a bad valve cover gasket. Each of them has its cause that every driver should keep in mind and check regularly.

What Are The Bad Valve Cover Gasket Symptoms?

Bad Valve Cover Gasket Cause Vacuum Leak

Burning Oil Smell

The worn-out cover is one of the most common causes of a bad valve cover gasket, represented by a distinctive burning oil smell through vents or from the engine. The smell may occur when your engine is idling, with the oil pouring out on the engine and burning up due to the heat.

If the engine oil light flashes on the dashboard, you should take a closer look at the engine. Oil drops are often found on the fuel intake, pipes, cylinder heads, or exhaust manifolds.

Rest assured; the quantity is insufficient to cause a fire, though you should get your car to a mechanic at your earliest convenience.

Rough Idle Within Engine or Misfire

Idle issues can happen in some car models. There, the valve also works as a seal to prevent oil from flowing into other engine sections, including the spark plug tubes, which are made in the form of rings.

It also helps retain the air flow between the parts. Once a gasket gets damaged enough, the oil will leak into the plug tubes.

When there’s enough oil in the tubes, the engine’s performance will reduce drastically, and misfires will be more likely to occur. Check engine light will flash intermittently when this happens.

Low Engine Oil

If the valve cover is not tended to in a long time, significant oil loss will cause trouble for the engine.

The internal engine will undoubtedly deteriorate due to not being lubricated enough. That’s not to mention extensive heat rising that will damage the internal engine blocks, leading to engine failure.

If you find out that your oil runs out without any particular reason, you should have your car carefully inspected. The biggest issue may lie in not only your valve cover but also in other leakage within the pipes.

Dirty and Greasy Valve Cover

Occasionally, the problem comes from the dirt and grease retained on the cover. An unsanitized valve cover contains a lot of dirt and little debris that will make the valve seal less effective.

This is usually the case when you see new oil leaking out after getting changed recently.

To tackle this issue, unlock the cover and clean it properly before putting it back in place. Remember to put an oil filler underneath to keep the engine oil and refuel it after finishing. A clean cover will work better.

How Do I Fix A Valve Cover Gasket Leak?

How To Fix A Valve Cover Gasket Leak

Step 1

To begin with, make sure that it’s a valve cover leak but not leakage at any other place. Take a close inspection thoroughly before deciding to unlock the valve.

Step 2

After that, remove all vacuum hose, cables, and electrical connectors attached to the gas valve cover.

If you have trouble remembering their original position, you should label them before unhooking. Remove the old spark plugs and remove the remaining oil in the dipstick tubes.

Step 3

Use a torque wrench and rags to clean the gunk on the inside. If your spark plugs are too old, replace them with new ones.

Remove the valve cover bolts around the valve and lift the cover off the engine.

Step 4

Once the old gas valve is out, install the new valve cover gasket in position carefully.

Clean all the dirt and oil on the surface if there’s any left since it needs to be spotless to hold the pressure.

Put the bolts in their original position before you take them off. Remember to reinstall all cables, hoses, and other components in labeled positions.

Step 5

Last but not least, use a new sealant to protect the cover, preferably silicone. This material is much more durable than plastic or rubber.

All you have to do is smear a medium amount of them over the joint, which is much more efficient and cost-saving.

Follow these steps carefully, and you will no longer have to rack your brain should a bad valve cover gasket cause vacuum leak!

Watch the below videos for more detail:

Can A Leaking Valve Cover Gasket Cause Rough Idle?

As mentioned in the article, yes. However, it only happens in some models, with spark tubes in the form of O-rings.

Modern electric car systems are built to prevent rough idle and protect the engine. You may experience leaky valve cover in older models.

How Do I Identify A Blown Valve Cover Gasket?

A blown valve cover gasket often comes with the following identifications:


For the most part, should a bad valve cover gasket cause vacuum leak, replacing it with a new one would cost about $20 for a new valve and about $4 or $5 for some silicone sealant.

If you go to a mechanic, the total cost may reach up to $100. So it would be much more efficient to learn to replace the valve cover yourself.

We hope you have learned how to deal with a bad valve cover gasket. Thank you for reading!

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