Chevy's 2.4L Ecotec Engine Uses an Excessive Amount of Oil
A series of unfortunate design decisions allow oil to end up in the combustion chamber of the 2.4L Ecotec engine. And a less-than-impressive oil monitoring system doesn't do anything to warn owners about dangerously low oil levels until it's much too late.
GM made updates to its 2.4L Ecotec engine for the 2010 model year that opened multiple ways for oil to get sucked into the combustion chamber where it's burned into oblivion. As the crankcase's oil level drops owners experience bucking at low speeds, engine knocks and ticks, fouled-up spark plugs, and irreversible damage to critical components like the timing chain.
And it's all made worse by an oil level monitoring system that doesn't do a darn thing until it's too late.
There is good news, however, as multiple settlements have extended protections to certain owners. Let's take a look back at how we got here.
GM switched to direct-injection for the 2.4L Ecotec engine in some 2010 models[1:1]. The new design relied heavily on low-tension oil control rings, spray jets, and a positive crankcase ventilation system to lower fricition, increase efficiency, and boost performance.
Each piston has multiple control rings to maintain compression, transfer heat, and keep oil out of the combustion chamber. That last responsibility falls on the oil control ring which is found at the bottom of the control ring stack. As the piston moves up and down, the oil control ring scrapes oil off the cylinder walls and prevents it from exiting the crankcase.
GM opted to go with a thinner, low-tension oil ring for the 2.4L Ecotec engine.
But the oil control rings GM chose are way too thin and wear down quickly allowing gaps to form in the ring's coating. Those gaps allow oil to sneak past and burn up in the combustion chamber.
To make matters worse, the Ecotec engine uses oil cooling jets to reduce piston temperatures. Lower temeratures means less fricition. Less fricition means longer durability and increased performance.
But the jets spray pressurized oil directly into the cylinders where frail oil rings are already struggling to keep oil in the crankcase. This allows even more oil than normal to sneak past and faulty or worn rings into the combustion chamber.
Faulty positive crankcase ventilation (PCV) system ∞
And because that's not enough, it's widely believed that the Ecotec has a defect in its PCV system. PCV plays an important role in engine efficiency, as it draws gas out of the crankcase, sending it through the intake manifold and back into the combustion chamber where it can be used.
But the Ecotec's PCV may be vacuuming more than just gas vapors as it also allegedly pulls oil off the valve trains and into the intake systems where it gets burned off.
TSB 15285C was released in March of 2016 and offered a real breakthrough towards addressing this problem.
While previous bulletins only offered software updates to reduce the recommended oil change intervals, TSB 15285C acknowledged oil consumption as an issue for the 2.4L Ecotec LAF engine due to worn out piston rings.
"Some 2011 model year Chevrolet Equinox and GMC Terrain vehicles, equipped with a 2.4L engine, may exhibit excessive engine oil consumption (less than 2,000 miles per quart of engine oil), due to piston ring wear."
Special coverage adjustment increases protections for 2011-2012 Equinox owners ∞
Originally for 2011 Equinox owners, the coverage eventually extended the warranty to 7.5 years / 120,000 miles for 2010-2012 owners. The coverage included any costs needed to replace the engine's 4 piston assemblues which is a time-consuming and expensive job.
This problem has been reported by owners of the following generations. While there's no guarantee it affects all the listed model years, most years within a generation share the same parts, manufacturing processes, and problems.