Engines · Volkswagen Group
Audi 2.5 TFSI five-cylinder (EA855) common problems
The 2.5 TFSI is Audi's 2.5-litre five-cylinder turbo petrol with chain-driven camshafts, launched in 2009 in the TT RS with an iron block and direct injection, and reworked from 2017 as the EA855 evo with an aluminium block, 400PS and both port and direct injection. It won International Engine of the Year several times running and is regarded as an otherwise strong engine; besides the cars below it powers the RS3 8Y and the Cupra Formentor VZ5.
Common problems and what to look for on the 2.5 TFSI
The known issues most worth checking when you view a car with this engine. None of them means a car is a bad buy, but they're worth knowing about before you buy, and a good history often shows they've been dealt with.
Misfires under load: spark plugs and coils
What to look for: Let the engine idle once warm and feel for a regular stumble. On the drive, accelerate firmly in a higher gear and note any stutter, hesitation or engine warning light. Look in the history for recent spark plugs and coil packs.
Why it matters: Misfires under heavy throttle, sometimes with a flashing engine warning light, are a known complaint, and on the RS3 8V new spark plugs usually cured them. Worn ignition coils give similar symptoms. Both are routine parts, and plugs changed on time are a good sign, especially on a tuned car.
Oil change history
What to look for: Check the service history for oil changes on time, ideally more often than the maximum interval, with the correct grade. Ask for the engine to be cold when you arrive and listen as it starts: it should settle quickly without any rattle.
Why it matters: The factory interval is up to a year or 10,000 miles, and careful owners often halve it; on the hard-driven RS3 8P, many treat 5,000 miles as the limit. The camshafts are driven by a chain, so there is no cambelt to change, and frequent changes with good oil are the best care for the chain and turbo. A full history with regular oil changes is reassuring.
Carbon on the inlet valves (iron-block engines)
What to look for: With the engine warm, let it idle and feel for roughness. On the drive, note any hesitation at low revs or loss of power. Ask whether the inlet valves have ever been cleaned.
Why it matters: The iron-block engines in the TT RS 8J, RS3 8P, RS Q3 8U and early RS3 8V inject fuel directly into the cylinders only, so nothing washes the inlet valves and carbon builds up. It causes rough running and lost power, and is cleaned off by walnut blasting. The evo engine from 2017 added port injection to counter it.
More known issues, covered in the full guide for each car
- Turbo wastegate rattle (earlier engines)
Cars with the 2.5 TFSI
- Audi TT RS 8J: TT RS 340PS (CEPA) and TT RS Plus 360PS (CEPB)
- Audi RS3 Sportback 8P: RS3 340PS (CEPA), from 2011
- Audi RS Q3 8U: RS Q3 310PS, 340PS and 367PS performance
- Audi RS3 8V: 367PS iron-block engine (CZGB) 2015 to 2016, then the 400PS aluminium-block evo (DAZA, later DNWA)
- Audi TT RS 8S: TT RS 400PS evo engine, all years
- Audi RS Q3 F3: RS Q3 400PS evo engine (DNWA)
A pre-purchase inspection guide for your car
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General points for the engine, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with any manufacturer.