2012–2018 Audi A6: Coolant leak or low coolant warning (3.0T water pump and thermostat)
Likely causes, ranked
- Leaking water pumpShop
- Leaking thermostat housingShop
- Crossover pipe O-ringsShop
Real-owner fix counts will appear here as reports come in.
DIY or shop: See DIY or shop section
Parts to check
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Symptom: A low coolant warning, coolant smell, or drips at the front of the engine.
Likely causes
- Water pump. AudiWorld and Audizine owners report 3.0T water pumps leaking, sometimes under 40,000 miles.
- Other leaks. Owners note the thermostat under the supercharger and the plastic crossover pipe can leak too.
DIY or shop?
Shop.
Useful steps
- Pressure test the cooling system.
- Find the exact leak.
- Use Audi-spec coolant.
Vehicle focus: 2012–2018 Audi A6.
Safety / mechanic note
Running low on coolant can overheat the engine. Verify with a mechanic or dealer.
Recalls & service bulletins
No recalls or service bulletins are listed for this page yet.
NHTSA complaints: 73 keyword-matched complaints for Audi A6 2012–2018 (of 248 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-15).
Always check your VIN for open recalls at nhtsa.gov/recalls.
Sources
What actually fixed it?
Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.