All engines require oil to lubricate and protect the moving parts of an engine from wear. These parts include cylinder walls, pistons and piston rings. When a piston moves down its cylinder, it leaves a thin film of oil on the cylinder wall. This tiny amount of oil partially gets consumed by the combustion process and therefore it’s normal to see a small amount of oil reduction is the engine.
What’s not normal, however, is to see the rapid and extreme oil consumption in the 2011 GMC Terrain.
Looking for information of excessive oil consumption in V8 Vortec engines?.
General Motors’ Technical Service Bulletin (TSB 15285C) could be of great interest to 2011 Terrain owners who’ve been complaining about excessive oil consumption.
Chevy and GMC dealers were told in previous technical service bulletins to install updated engine control module calibration and perform an oil consumption test. This time dealers are told to diagnose the problem and replace the pistons … General Motors says repairs will be made free of charge based on warranty coverage extended to 7.5 years or 120,000 miles, whichever comes first. The coverage begins from the date of sale of the SUV.
This is great news for Terrain owners.
According to a GM bulletin, the most common cause is stuck oil control rings. Generally the stuck oil control rings are the result of excessive oil on the cylinder walls and this excessive oil can come from the PCV system and/or the AFM pressure relief valve in the oil pan.
Upon inspection of an engine experiencing this problem, you will typically see an oil-fouled spark plug. Although excessive oil may also show up in the intake manifold.