When it comes to sealing an engine, the gasket is the hardworking soldier that takes a tremendous amount of abuse but is typically never recognized for its effort. One of the most important gaskets that keep cylinder head hardware protected from the elements and keeps oil from escaping from your motor is the valve cover gasket. Most valve cover gaskets are made from plastic or cork and are used as a seal between the cylinder head and the valve cover itself.
Although the valve cover gasket is well protected from the top and bottom, it is very delicate and prone to damage from the sides. Over a period of time the gasket becomes brittle and will crack due to exposure to dirt, debris, heat and other elements. When this occurs, the gasket can lose its integrity and will leak, potentially causing cosmetic issues with leaking oil or reduced engine performance. If not replaced by an ASE certified mechanic in time, it can lead to complete engine failure.
There are a few common symptoms that will indicate a potential problem with a bad or failing valve cover gasket. If you recognize any of these warning signs, contact a mechanic as soon as possible so they can replace the valve cover gasket if needed.
1. Burning oil smell
When a valve cover gasket is pinched, worn out or cracked, compressed oil from underneath the valve cover will find a way to escape. When this happens while the engine is running, the excess oil will drip on the cylinder head, fuel intake or in some cases, the exhaust pipes. These are all hot components that will burn the oil and produce a burning oil smell that is easily recognized by any average car driver. If you smell burning oil, contact a professional mechanic so they can properly diagnose the cause of the oil leak and fix the problem.
2. Valve cover is dirty and leaking oil
During most oil changes, the technician will inspect the valve cover to see if there is any leaking oil coming from the valve cover gasket. The quickest indication of this problem is when the valve cover / cylinder head is very dirty. Oil collects dirt and debris under the hood and will appear to be "caked" on the valve cover or cylinder head. If you have the oil changed, or look under your hood for any reason and discover that the valve cover is dirty, it's most likely caused by a bad valve cover gasket.
3. Engine is low on oil
As oil leaks from the valve cover gasket, it obviously leaves the oil pan. When this situation happens frequently, it can cause the Engine Oil Light to appear on your dashboard. If the engine oil is low, it will reduce its potential to properly lubricate the internal engine components. This can build up excessive heat inside the motor and cause serious engine damage. If you notice the Engine Oil Light is illuminated at any time, don't delay or assume it will stop glowing. Contact a good mechanic to diagnose the problem and repair what is causing the oil leak.
4. Engine is running rough and causing misfires
Sometimes when oil leaks from a valve cover gasket it leaks all the way down to the spark plug galley and eventually seeps inside the spark plug tubes. This will cause a misfire or reduce engine performance. It can also cause a fire under your hood if it goes unrepaired.
In all of the above scenarios or warning signs, the root issue is typically caused by a valve cover gasket that has broken, is pinched, or has been improperly applied if new. When you notice these symptoms, contact a local ASE certified mechanic to diagnose the problem and replace the bad valve cover gasket correctly.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Valve Cover Gasket and was authored by Timothy Charlet.