On these engines the oil pump is driven by its own small toothed belt, and that belt runs in the hot engine oil. This is not the large timing belt that drives the camshafts, it is a separate belt in the lower part of the engine. In the oil the rubber hardens over time, its surface starts to crumble, and the loose particles block the suction side of the oil pump, so the oil pressure drops. If the belt snaps, the oil pump stops at once and the engine is left without lubrication within seconds. The rubber crumbs can also ruin the turbocharger and the camshaft adjuster, because they are lubricated from the same oil circuit. The maker specifies no replacement interval for this belt, so most cars still carry the one fitted at the factory, and the failures are reported above 150,000 km. Oil outside the specification and a stretched oil change speed the process up, because this belt ages in the oil. Replacing the belt itself costs between 200 and 600 euro, as long as the engine has not run without oil pressure.

On short urban trips the particulate filter cannot burn through. The engine control unit then injects extra fuel late in the cycle to heat the filter, and part of that fuel passes down the cylinder wall into the sump. The oil level rises, the oil thins out, and it lubricates worse.

On AdBlue (SCR) diesels the NOx sensor after the catalyst ages, and the tip of the dosing valve crystallises. An AdBlue warning appears on the dash, often with a countdown ("X km of starts remaining"), while the tank is full. Crystallisation typically forms with short trip, urban use, or from poor quality AdBlue; on a car standing below freezing the circuit can freeze up too.

The internal springs of the flywheel tire, and the two discs knock against each other. The signs are a rattling or knocking from the bellhousing at idle and when releasing the clutch pedal, and vibration through the floor. If the clutch slips without a burnt smell, that also points to the flywheel. It is worth replacing in time: a disintegrated flywheel can destroy the bellhousing too. At a clutch replacement the two go together anyway.

On the EA288 the coolant pump is demand-controlled, and after replacement the cooling circuit cannot be filled the old way. The Schaeffler/INA repair specification requires the system to be filled with a vacuum device and bled with a diagnostic tool, following the vehicle manufacturer instructions.

The seven speed dry DSG often starts shifting hesitantly as early as 30,000 to 50,000 km: it does not shift smoothly, sometimes it cannot find the gear, and it jerks worst in slow, congested traffic. The cause is wear of the clutch pack and the mechatronics unit. Many people skip the oil change because they believe it is a lifetime fill, and most DSG faults come from that.

The stop-start drops out as early as 20,000 to 35,000 km, typically on the 1.0 TSI and 1.6 TDI versions. The cause is the condition of the battery.