The EGR cooler cools the recirculated exhaust gas before it enters the intake again, and coolant flows through it while it does so. The temperature difference between the two sides is large, so the wall can crack or the gasket can let through, and then the coolant reaches the exhaust or the intake side. This leaves no puddle under the car and the place of the leak is not visible from outside: the coolant evaporates and the level drops slowly, over weeks. The accompanying signs are whitish smoke, a rising coolant temperature, raised pressure in the cooling system and a sweetish smell. If it goes on for months the cylinder head can be damaged too, because the cooling gradually gets worse. On the EA189 engines the fault code P2425 usually comes with it. The problem is reported above 100,000 km, and replacing the cooler costs 600 to 1,500 euro.

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.

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.

Magnetic Ride is an adaptive damper you order separately, the damper uses a magnetic fluid, which is what lets it go firmer or softer, and if it leaks the system reports a fault. Even one damper costs more than 1,000 euros, and they are usually replaced per axle, so as a pair. First check whether the car has it at all, because it was an option and a listing rarely says, and if it does, ask whether any have already been replaced.