How to Confirm That Your Valve Cover Gasket is Failing

Underneath the valve cover, you’ll find a valve cover gasket between the cover and the cylinder head. The gasket is there to prevent oil from seeping out. The cylinder head subjects the gasket to a lot of heat. Heat can cause the gasket to become brittle and crack or shrink over time. As a result, the gasket fails to do its job, and oil leaks out.

What Happens When the Valve Cover Gasket Starts Leaking Oil

Valve cover gasket

Image Credit: SuperChevy

A valve cover gasket leak is pretty serious. The bigger the leak, the faster the engine loses oil. If this goes on for too long, the engine won't be properly lubricated, and may suffer engine damage. So it's best to fix the leak right away.

Confirming a Leak in the Valve Cover Gasket

The best and most thorough way to diagnose a leaking valve cover gasket is to look over the whole perimeter of the valve cover and gasket from the top.

To help make this process easier for you, we put together a step-by-step guide on doing this.

  1. Drive around your car for a while; long enough to warm up the engine.
  2. Let the engine cool off.
  3. Take off the engine cover. Now, you can to see the valve cover.
  4. With a flashlight, carefully inspect the valve cover gasket area. Look for:
    1. Any oil – old or fresh – leaking out of the gasket area
    2. Loose bolts
    3. Missing bolts
    4. The valve cover gasket sticking out from under the cover at any point
    5. Dirt and residue on the edge of the valve cover

How to Know if the Problem Lies With the Valve Cover Instead of the Gasket

Sometimes the valve cover gasket is intact and firmly in place, but the valve cover itself is damaged. When you have a cracked or loose valve cover, oil will leak out just like with a broken gasket.

How can you confirm that the valve cover is the problem, though?

It’s easy to see the valve cover from the top. So if you see oil leaking out from above the gasket area, then chances are high that the valve cover is cracked or loose. You just have to pinpoint the location of the leak on the cover.

If you can't pinpoint the leak, wash the engine, let it dry, and repeat the process.

So There’s a Leak; Now What?

New Gasket

Image Credit: SuperChevy

If you found a leak in the valve cover or the valve cover gasket (or both), the part needs to be replaced right away. You have two options:

  1. Pay a GM dealership to replace it for you
  2. Replace it yourself at home

Having a dealership replace the part for you is obviously the more expensive option. You would have to pay them $100 per hour (give or take) and a markup of about 30% for the replacement part. If you ask us, it’s not worth the extra cost. Replacing your valve cover and/or valve cover gasket is so easy a novice could do it. To see what we mean, here's a tutorial on replacing a valve cover gasket on a Chevy Colorado. Also, you can save a bunch of money by ordering a genuine OEM replacement part from a trustworthy online seller.

Some online sellers mark up their prices, though, so you’ll need to find one that offers low prices. You don’t need to look far, because you can find deep discounts right on our website. A few examples:

  • Valve cover #25198877 (for 2018 Encores, Sonics, and Traxes) normally costs over $75, but you can buy it from us for under $50.
  • Valve cover #55564395 (for 2009-2018 Aveos, Cruzes, Sonics, and G3s) normally costs over $160, but you can buy it from us for under $105.
  • Valve cover #12631008 (for 2007-2012 Colorados, Canyons, and H3s) normally costs over $175, but you can buy it from us for under $114.

To see our entire catalogs of valve covers and valve cover gaskets, check out the following links:

Please contact us for assistance if you have trouble finding the right valve cover and/or gasket for your GM vehicle.