What Are the Causes of High Engine Oil Consumption?

All motor vehicles need oil. It’s the slick stuff that lubricates the engine, prevents friction and protects all the moving parts from wearing and tearing each other down. Without it, things would quite literally grind to a halt.

That’s why it’s critically important that a vehicle’s oil is changed regularly – over time it gets dirty and littered with debris particles that make it less effective – and the oil level be maintained.

Excessive oil consumption can be a symptom of significant problems with the automobile, and can itself become a problem.

What Is Oil Consumption?

Every car, truck and SUV on the road consumes oil. But not all the oil that’s put in stays in. Regular oil consumption happens for several reasons that are completely normal.

Over time, some of the oil just evaporates, or burns off as the engine works. Synthetic oils evaporate at a slower pace than conventional motor oils, according to Popular Mechanics, but they still evaporate. And lighter viscosity oils burn up more quickly than thicker oils.

The age of the engine also plays a role in oil consumption. “At the beginning of an engine’s life, it will have a break-in period in which it will consume a higher level of oil,” automotive website AxleAddict explains. “After an engine is fully broken in, it will consume less oil.” But when the engine approaches the end of its life, it will again consume more oil.

Hauling heavy loads or driving in extreme conditions such, as off-roading or severe inclines, can place a heavier demand on an engine and that will also lead to increased oil consumption, AxleAddict says.

How Much Engine Oil Consumption Is Normal?

Exactly how much oil that a vehicle operating in normal conditions will consume varies widely according to the type of vehicle, the type of engine and the individual car, experts say. Generally speaking, one quart of oil in a standard vehicle should last more than 3,000 miles. In some newer cars, a quart of oil might last in the range 7,000 to 10,000 miles, especially if it’s a synthetic oil.  High-performance vehicles can go through the same amount of motor oil in less than 3,000 miles though.

What Causes High Engine Oil Consumption?

Excessive oil consumption can be symptomatic of other problems with a vehicle, some simple and others complex. Among the more obvious causes are leaks, usually from a valve cover seal or an oil pan gasket. Dirty oil can also lead to higher than normal oil consumption as the debris it carries can clog the pistons and wear on other parts, forcing them to work harder and use more oil.

Several defects or malfunctions can also result in an engine burning an excessive amount of oil. Broken or worn out piston rings and ring belts can allow the oil to pass through them and seep into the engine where it will be burned off. Too much oil in the crankcase can also lead to excessive burn-off. An engine may flood if the oil pressure is too high, pushing the oil into the cylinders where it will burn off.

Engines are a series of moving parts carefully orchestrated to produce motion and when the timing on one or some of those parts is off it can strike a sour note. If valves and pistons are not moving in synchronicity, a vacuum can form that draws excess amounts of oil into the combustion chamber, where it eventually burns off, according to the automotive company Highway and Heavy Parts. Restrictions on an engine’s air intake can also create a vacuum that pulls oil into the combustion chamber.

Whatever the cause, excessive oil consumption can cause serious mechanical problems if left unchecked. In a worst-case scenario, a vehicle that runs out of motor oil can end up with a seized engine.

What Are the Warning Signs to Look Out For?

Regularly checking a vehicle’s oil level is the most reliable way to monitor its rate of oil consumption. Most automotive experts recommend checking the oil once a month. Any sharp drop in the oil level will alert the driver to a problem.

Other common signs of excessive oil consumption include the smell of burning oil while driving and the sight of oil marks left under the vehicle when it’s been parked.

Have You Been Affected by Poor GM 5.3 Engine Oil Consumption?

Customers who own one of several of General Motors trucks and sport utility vehicle models manufactured between 2011 and 2014 have reportedly had so many oil consumption problems that they’ve filed a class action lawsuit.

Carcomplaints.com reports that the class action lawsuit against GM involves the automaker’s Generation IV 5.3L V8 Vortec engines, which plaintiffs claim is defective and “causes excess oil consumption, spark plug fouling, poor running condition, and premature engine wear.” The GM models cited as problematic are the Chevrolet Avalanche, Silverado, Suburban and Tahoe, and the GMC Sierra, Yukon, and Yukon XL.

“The Generation IV Vortec 5300 Engine causes excessive oil consumption that is allegedly far in excess of industry standards for reasonable oil consumption,” says Carcomplaints.com. “It results in low oil levels and insufficient lubricity levels which can lead to internal engine component damage.”

According to the report, the class action blames the excessive oil consumption, in part, on faulty piston rings that fail to keep oil in the crankcase. The complaint also claims that the active fuel management system in the affected vehicles overloads the piston rings with oil.

Finally, the GM class action lawsuit says affected vehicles’ oil monitoring systems wait too long to warn drivers when the motor oil level is low, which creates a greater risk of engine damage.

Owners of Chevrolet Avalanche, Silverado, Suburban or Tahoe, or GMC Sierra, Yukon or Yukon XL, manufactured between 2011 and 2014, that are experiencing excessive oil consumption – particularly those in Arizona, Colorado, Florida, Louisiana, Maryland, Minnesota and Wisconsin – may qualify to participate in the ongoing class action lawsuit.

Join a Free GM Engine Oil Consumption Class Action Lawsuit Investigation

You may have a legal claim if you purchased a new or used model year 2011-2014 Chevrolet Avalanche, Chevrolet Silverado, Chevrolet Suburban, Chevrolet Tahoe, GMC Sierra, GMC Yukon, or GMC Yukon XL with an LC9 engine.

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This article is not legal advice. It is presented
for informational purposes only.