The Audi BUH is a 1,798 cc, inline — four petrol engine produced between 2010 and 2016. It features turbocharging, direct fuel injection (TSI), and dual overhead camshafts (DOHC) with variable valve timing. In standard tune, it delivers 125 kW (170 PS) and 250 Nm of torque, offering a balance of responsiveness and efficiency for compact and mid — size Audi models.
Fitted to models such as the 8J A3, 8P A4, and 3C A6, the BUH engine was engineered for drivers seeking refined perfo…
Production years 2010–2016 meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/5678).
The Audi BUH is a 1,798 cc inline-four turbo petrol engineered for compact and mid-size models (2010–2016). It combines turbocharged direct injection (TSI) with variable valve timing to deliver responsive low-end torque and smooth acceleration. Designed to meet Euro 5 standards, it balances performance with regulated emissions and fuel economy.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,798 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 82.5 mm × 84.5 mm | |
Power output | 125 kW (170 PS) @ 5,100–6,000 rpm | |
Torque | 250 Nm @ 1,500–4,500 rpm | |
Fuel system | Bosch HDEV5 direct injection (up to 150 bar) | |
Emissions standard | Euro 5 | |
Compression ratio | 9.6:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single-scroll turbo (Honeywell) | |
Timing system | Chain-driven (front-mounted; tensioner wear documented) | |
Oil type | VW 502 00 / 505 00 (SAE 5W-30) | |
Dry weight | 127 kg |
The Audi BUH was used across Audi's 8J/8P platforms with transverse mounting. This engine received platform-specific adaptations-shorter intake manifolds in the 8J A3 and revised cooling routing in the 8P A4-and from 2013 the facelifted 8J models adopted the updated chain tensioner system, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The BUH's primary reliability risk is timing chain wear on early builds, with elevated incidence in stop-start urban use. Internal Audi quality reports from 2014 noted a significant share of pre-2013 engines requiring chain repair before 120,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to EGR clogging in city-driven vehicles. Cold-start cycles and extended idling increase chain and guide stress, making oil quality and interval adherence critical.
Analysis derived from Audi technical bulletins (2012-2016) and UK DVSA failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The BUH delivers strong performance and efficiency, but early models (2010–2012) had reliability concerns, especially timing chain failures. Later revisions (post-2013) improved chain durability, so well-maintained examples can be quite robust. Regular servicing and using high-quality oil (5W-30 VW 502 00) greatly aid longevity.
The biggest issues are timing-chain wear (leading to rattling or breakage), turbocharger oil coking, and intake swirl flap failure. Other complaints include oil leaks from gaskets and occasional EGR or lambda sensor faults. These are well-documented in Audi service bulletins.
This 1.8L TSI petrol was used in the A3 (8J), A4 (8P), and A6 (3C) models from 2010 to 2016. It primarily powered the 35 TFSI and 2.0 TFSI variants. The engine was phased out in favour of the EA888 Gen 3 series after 2016.
Yes. The BUH is highly tunable. ECU remaps routinely gain +30–50 kW safely on stage 1, as the stock internals handle torque well. Aftermarket upgrades (intercooler, exhaust, intake) can boost power further. Enthusiasts frequently remap A3 and A4 models for improved throttle response and top-end power.
Very good for its performance. In an A3 35 TFSI (125 kW) from around 2012, typical consumption is ~8.2 L/100km (city) and ~5.3 L/100km (highway), or about 43 mpg UK combined. Real-world figures depend on driving style, but expect 38–45 mpg (UK) on mixed roads for a healthy BUH engine.
Yes. The BUH series (like most modern Audis) is an interference engine. This means if the timing chain jumps or breaks, pistons can strike open valves, causing catastrophic engine damage. That's why chain maintenance is critical—any warning rattles should be addressed immediately.
Audi specifies a 5W-30 synthetic oil meeting VW 502 00 / 505 00 spec. Always use a quality oil designed for turbocharged petrol engines and change it at regular intervals (around 15,000 km or as Audi recommends) to ensure proper chain lubrication and minimize sludge buildup.
Comprehensive technical documentation and regulatory references
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GOV.UK: Vehicle Approval & V5C
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
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