Audi A5 45 TFSI B9

The EA888 Gen 3B uses an integrated water pump and thermostat housing made partly of plastic. The O-ring seal swells from oil exposure over time, and the plastic housing can crack under thermal cycling. Symptoms include low coolant warnings, puddles under the car, and erratic temperature readings. This is the most commonly reported failure on B9 2.0 TFSI engines, widely documented across A4, A5, and Q5 forums. Many owners report the issue appearing between 60,000 and 100,000 km, though some early examples fail sooner. When one component fails, specialists recommend replacing both the water pump and thermostat housing together due to the integrated design. Independent shop repair costs approximately 800 to 1,100 euros (parts 350 to 500 euros, labor approximately 3.5 hours). Audi dealers typically quote 1,300 to 1,500 euros. Aluminium aftermarket housings from GRAF or similar are more durable than the original plastic. The eight-year water pump coverage frequently quoted online comes from a United States class-action settlement and has no European equivalent, so budget for the repair and ask an Audi dealer about goodwill only as a bonus.

The EA888 Gen 3B injects fuel both directly into the combustion chamber and through a second set of port injectors in the intake manifold. Audi added that combined FSI and MPI system precisely to keep the intake valves washed, so the heavy valve coking that plagued first- and second-generation TFSI engines is far less common here. It is not impossible: a car used almost entirely for short cold trips, or one running with a torn PCV diaphragm feeding oil vapour into the intake, can still accumulate enough carbon to cause a rough cold idle, hesitation during acceleration, and minor misfires, usually well beyond 120,000 km. Walnut shell blasting is the standard cleaning method. Independent specialists charge 600 to 800 euros, while Audi dealers charge 1,000 to 1,500 euros. Treat a rough cold idle on a high-mileage short-trip car as a reason to inspect the intake rather than as a normal characteristic of this engine, and fix a failed PCV valve promptly because it is the fastest route to deposits.

The 45 TFSI produces 370 Nm of torque, which is near the DL382's design limit of 400 Nm. This means the clutch packs work harder than on the 40 TFSI (320 Nm), particularly during spirited driving or when launching from standstill. Symptoms include jerky 1st-to-2nd gear shifts at low speed, delayed engagement from standstill, and occasional gearbox malfunction warnings. The mechatronic unit (electronic valve body) can fail, with the G676 driver position sensor being a documented weak point. Problems typically appear between 80,000 and 120,000 km, especially if the transmission fluid was never changed. Audi's own UK service schedule calls for an S tronic oil and filter change generally before every 38,000 miles, roughly 60,000 km, so a seller describing the DL382 as a sealed lifetime fill is a sign the service was skipped rather than a statement of Audi policy. Mechatronic repair at a specialist costs 1,200 to 2,000 euros; full gearbox rebuild runs 2,500 to 3,500 euros. Any aftermarket software tune pushing torque above 400 Nm will significantly accelerate clutch wear.

The PCV valve on the EA888 Gen 3B contains a rubber diaphragm that deteriorates over time, typically between 70,000 and 120,000 km. When it tears, symptoms include rough idle, a hissing or whistling noise from the engine bay, increased oil consumption, boost leaks causing power loss, and check engine light with lean or rich mixture codes. Diagnosis is straightforward: check for vacuum at the PCV breather port cap. The valve itself costs 50 to 80 euros for an OEM replacement. Labor requires removing intake components and takes approximately 2 to 3 hours. Total repair at an independent shop runs 250 to 350 euros; Audi dealers charge 400 to 500 euros. A failed PCV valve also accelerates carbon buildup on the intake valves, so it should be addressed promptly.