In the 1.8 and 2.0 engines labeled TSI or TFSI from the EA888 series, pistons with very thin rings were used to reduce friction (by reducing the friction surface). Lowering energy losses due to friction was intended to reduce fuel consumption and, consequently, CO2 emissions, in order to meet increasingly stringent EU standards. Unfortunately, the use of such thin rings was a design flaw in these engines. It turned out that they are too delicate and do not effectively perform their function of scraping oil from the cylinder walls, leaving a significant amount of it in the combustion chamber. The oil that remains on the cylinder walls is burned during the combustion stroke. Therefore, these engines consume large amounts of oil from the very beginning of their use. The thin rings also wear out very quickly, causing increasingly poor oil scraping. More and more oil is burned. Additionally, the burning of oil in the engine cylinders creates carbon deposits, which cause the rings to stick in the piston grooves, resulting in the rings scraping even less oil and the oil consumption increasing even faster, becoming more and more problematic. This is what an old piston removed from a 2.0 TFSI engine with 84,000 km, which was already burning over 1 liter of oil per thousand kilometers, looks like.
The carbon that forms during oil combustion gets between the piston and the cylinder wall, causing vertical scratches on the cylinder surfaces.
Carbon from burnt oil also deposits on the valves, sometimes leading to their incomplete closing, and to the wear of valve stems in their guides.
Carbon deposit traveling with the oil can lead to the clogging of oil passages, resulting in a lack of lubrication, which leads to the seizure of components. The photo shows the upper part of the head with seized camshafts.
