Audi's legendary five-cylinder engine has evolved since it first appeared in the Audi Quattro. Audi's modern turbocharged straight five in its RS models is a brilliant performer, but Deutsche Auto Parts claims in a recent video that the high-horsepower engines rarely build up a lot of mileage – meaning we don't know how they play out in terms of reliability.So, the channel went out and found an Audi RS3 with 140,000 miles on the clock, pulled the 2.5-liter turbocharged engine out, and tore it apart for a close examination. Here's how the I5 screamer fared after considerable use. 2017 Audi RS3 2.5-Liter Turbo Teardown YouTube/Deutsche Auto Parts In 2017, the Audi RS3 made 400 horsepower with 354 lb-ft of torque, which hit low in the rev range at just 1,700 rpm. It's still a wicked little engine in 2026, but 140,000 rounds is a lot for something boosted and highly strung. The first thing to look for are leaks, which wouldn't be a surprise in a car this old and well driven. There aren't any, but that doesn't mean it hasn't had one or two that were taken care of by the previous owner.2017 Audi RS3DrivetrainAll-Wheel DriveTransmission 7-Speed AutomaticHorsepower400 hpTorque354 lb-ft @ 1700 rpmCurb Weight3,593 lbsAccording to Deutsche Auto Parts, water pumps are a common failure point on these engines but, on all cars, water pumps have a hard life and this one looks fine. The same goes for the turbo. There is some buildup of carbon in the valves, which probably shouldn't be that heavy on a port and direct-injection engine. Inside the engine, everything is nice and clean, but the timing chain tensioner desperately needs replacing.Mechanically, everything looks good, except for more signs the timing chain was destined to become a problem. With the head removed, the variable timing system is showing some wear, which is concerning. It doesn't look like any of the rocker rollers are causing a problem, but the cam is certainly wearing and that's an expensive part to replace.It's possible the wear is caused by the oil, which looks and allegedly smells, like it's been contaminated by E85 fuel. That's not good, because E85 is ethanol based, and ethanol has a negative effect on oil – oxidizing it and causing it to break down. As Deutsche Auto Parts explains, if an engine is being run on E85 fuel, then oil changes should happen more often. The common recommendation is half the mileage interval the manufacturer recommends. Verdict: Not Too Shabby, Timing Notwithstanding YouTube/Deutsche Auto Parts The 140,000-mile RS3 engine has held up well, and Audi has clearly built it to last, barring the plastic part in the timing chain tensioner. The wear we see that's concerning likely boils down to oil changes not being frequent enough while being run on E85 fuel. Ultimately, engine wear and failures almost always boil down to oil, whether it's because the engine is carelessly maintained or some other issue that affects oil quality.Source: Deutsche Auto Parts / YouTube