BUH

RS6·C6·2008–2010

"Forum data is extremely limited for this specific engine code — buy with eyes wide open."

RISKY

42/ 100

"Complex, expensive, data-scarce performance machine"

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Max HP

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Torque Nm

10,000

Oil interval km

Recalls

Known issues

Known Issues

Timing Chain Wear and Rattle€1,500-4,000 · 80,000-160,000 kmHIGH

Timing chain rattle on cold start is a documented concern across the Audi C6 platform. Forum references note cold-start chain rattle lasting several seconds, which can indicate stretched chain or worn tensioners. On a high-performance engine, neglected chain issues can escalate to catastrophic failure.

Cold-start rattling noise from engine front

Intermittent rattling during warm-up

Timing-related fault codes

VAG-COM Group 93 camshaft deviation readings out of spec

DIY: Expert

EGR Cooler Integrity (Platform Risk)€500-1,800 · 100,000-200,000 kmMODERATE

While EGR cooler failures are primarily documented on the 3.0 TDI variants sharing the C6 platform, the BUH engine code appears in parts listings alongside TDI-equipped A6 C6 variants. EGR cooler leaks can cause coolant loss and potential engine damage if undetected.

Coolant level dropping without visible external leak

White smoke from exhaust

Overheating warnings

Coolant contamination

DIY: Advanced

Glow Plug Failure (Platform-Wide)€100-400 · 60,000-120,000 kmLOW

Glow plug issues are repeatedly mentioned across A6 C6 forum discussions. While more relevant to diesel variants, electrical ancillary issues on ageing C6-platform Audis are common. Verify all warning light behaviour is appropriate for the engine type.

Flashing glow plug warning light

Limp mode engagement

Hard cold starts

DIY: Moderate

Buying Checklist

Connect VAG-COM and check Group 93 for timing chain camshaft deviation — any significant offset is a red flag

Listen for cold-start timing chain rattle; let the car sit overnight before inspection if possible

Pressure-test the cooling system and inspect for EGR cooler or coolant hose seepage

Check full service history for oil change intervals — accept no more than 10,000 km between changes on this engine

Scan all modules for fault codes, especially engine, transmission, and any climate/heater valve codes

Verify the heating valve and coolant distribution components are not leaking — BUH is cross-listed in C6 coolant valve parts groups

Service Reality

Community oil interval10,000 km

Oil specification5W-40 fully synthetic meeting VW 502.00 / 505.00 (verify against engine spec plate)

Est. ownership cost (2yr)€2,000-5,000 per year depending on mileage and maintenance history

Real mix fuel consumptionNo data

Also Found In

Audi A6 C6 (parts cross-reference confirmed in forum listings)

Buying Advice

The Audi RS6 C6 BUH is a complex, high-performance vehicle with very limited community reliability data available for this specific engine code — this alone warrants caution. The C6 platform is known for timing chain concerns and EGR cooler risks on related engines, and a pre-purchase inspection by an Audi specialist with VAG-COM is non-negotiable. Budget generously for maintenance and potential repairs, as parts and labour costs on RS-grade vehicles are significantly higher than standard A6 variants. Only purchase with a clean bill of health from a specialist inspection and a fully documented service history.