In 2015 General Motors recalled 1.4 million cars in the U.S. for oil leaks due to failing valve cover gaskets that had been causing cars to catch fire (1). As a result, more than one thousand cars were reported to have caught fire. Besides, a number of injury cases were also reported. Not to mention that these are the cases that were reported only in the United States.
The valve cover gasket is one of the most important gaskets in the engine. It protects the cylinders, pistons, connecting rods, bearings, camshafts, timing belts, and other components that make up your engine by sealing out dirt, moisture, and other contaminants from entering the engine. Besides, it also keeps oil inside by maintaining pressure on it. Absence of required pressure
increases friction which leads to severe engine damage.
All the car manufacturers warn of the serious damage which may occur due to low oil pressure. For example, Japanese car manufacturer HONDA even warns the owners that running the engine with low oil pressure can cause serious mechanical damage almost immediately (2).
Symptoms of a Bad or Failing Valve Cover Gasket
A bad or failing valve cover gasket can cause several different symptoms. Here are some of the most common symptoms that can help you identify a bad valve cover gasket.
A puddle of coolant or oil underneath the car when parked
If you have a valve cover gasket leak or bad valve cover gasket, you will notice an oily or wet spot on your driveway or garage floor when you park your car. The leak may also cause your car’s temperature gauge to rise if it is running hot or overheat if it is not running at all. You may also see steam coming from under the hood of your car when it’s idling in traffic and smells burning oil.
Foul exhaust smell
The valve-cover-gasket-leak symptoms can be laborious to identify. This oil leak can cause a foul exhaust smell in your car. The smell will be more noticeable when the engine is cold because there is less heat to dissipate the fumes. In addition, the valve cover gasket seals the engine’s valve train, located between the cylinder head and the engine block. If this seal breaks down, then gases can escape into the cabin. Some mistake this smell for gas, cigarette smoke, or even burnt toast.
Engine oil leaks from the area around the valve cover or oil filter housing
Valve cover gaskets are rubber or cork seals that seal the valve cover to the engine block. Valve covers are a common source of oil leaks in engines. For example, if you notice oil on your driveway, and it is coming from around the front of the engine, you may have a valve cover leak. Oil may also be dripping from under the car near the front of the engine. An issue typically causes a leaking valve cover gasket with the gasket, such as age deterioration or installation error, resulting in coolant leaking into areas where it should not be.
Rough idle and hesitation when accelerating
Rough idling and misfire are also the symptoms that mirror a faulty and leaking valve cover gasket. Due to a failing valve cover gasket, engine oil seeps inside the sparkplug tubes, which causes rough idling or misfire. If the leakage problem persists and is not addressed timely, it can contaminate a sparkplug to the point of saturating its insulator and electrode. Which, in turn, may demand sparkplug replacement.
Oil in engine coolant (may be seen as black sludge)
If you think your car’s engine is suffering from a bad or failing valve cover gasket causing an oil leak, you have to look for oil in the coolant. If you see oil in the coolant, it could mean that your valve cover gasket is leaking.
Engine hesitation or stalling when driving at higher speeds
Stalling engine, especially at higher RPMs, is another significant symptom of a leaking valve cover gasket. At higher RPMs, engines undergo a process where every component performs superfast. However, the oil that seeps inside the engine affects the performance of these components and leads to engine hesitation or stalling.
White smoke coming from the exhaust pipe during engine operation
White smoke from the exhaust pipe during engine operation is another valve cover gasket leak symptom. The white smoke is caused by oil and other fluids that leak from the valve cover gasket and into your exhaust system.
What Causes Valve Cover Gaskets to Fail and How to Resolve this Issue?
On average, valve cover gaskets last at least 40,000-60,000 miles. In some cases, they are found to last considerably longer. However, with time, gaskets become brittle due to the factors like age, heat, cold, and maintenance issues. Due to brittleness, gaskets fail, and valve covers leak oil. Below are some of the causes which lead to an engine-oil leak and valve cover gasket failure.
Not Starting a Car on a Regular Basis
Engine oil contains multiple additives which prevent all the components from deterioration. However, when an engine is not started for an extended period, like every other component, the engine’s valve cover gasket wears out due to the non-availability of oil.
Infrequent Oil Changes
As mentioned earlier, engine oil contains additives that ensure the longevity of gaskets by moisturizing them. Used oil, after a certain period, loses these additives. If oil is not changed timely or as per the recommendations/instructions of the manufacturer, the valve cover gasket may fail
Over/Under Tightened Valve Cover Bolts
Many times, it happens that to resolve the oil leakage problem, people spend a lot of money and have worn-out gaskets replaced. However, the issue persists. If an engine’s valve cover bolts are not torqued properly upon installation of a new gasket, there are increasing chances that oil leakage will stay. This is because the gasket’s surface gets flat and deshaped when bolts are over-tightened. Eventually, it leaves room for oil leakage. Whereas, if bolts are under-tightened seal is not formed between the valve cover and engine. Resultantly, oil leaks outside.
All the components of an engine have the capacity to operate at a set level of temperature. When the engine’s temperature goes above that pre-determined level, all the components start failing. When the engine’s temperature rises above normal, the gasket becomes heat stressed. Heat stress poses an accelerated risk of cracking and blowout.
Ways to Avoid and Fix This Problem
(1) Even if your car is not in your use, start at least once a week and let it run for about 5-10 minutes. It’s necessary not only for the valve cover gasket but also for your car’s overall health.
(2) Always use the oil which your car’s manufacturer recommends.
(3) Always change your car’s engine oil in time and as per the recommendation of your car’s manufacturer. Only risk your car’s engine by going above the recommended miles with an oil change.
(4) If your car is suffering from a bad or failing valve cover gasket, try to have it replaced in the workshop of your car’s manufacturer or by an experienced mechanic.
Cost of Replacing a Bad Valve Cover Gasket
The average cost of replacing a valve cover gasket varies from $100-$400. According to rough estimates, you can expect to pay around $20-$300 for a new valve cover gasket, depending on the vehicle model, the make year, and your country. In addition, labor time may take around 1-4 hours, depending on the complexity of the engine, which may cost $60-$400.