Table 1 shows one common engine and engine cooling related problems of the 2019 Audi S5.
| Problem Category | Number of Problems |
|---|---|
| Engine And Engine Cooling problems |
I am writing to file a formal safety defect complaint regarding the ea839 3. 0t turbocharged v6 engine installed in various Audi models, including but not limited to the b9/b9. 5 s4 and S5, c8 a6 and a7, and 4m/4m. 5 q7 and q8 (model years approximately 2017 onward). This engine has a well-documented issue with piston skirt wear and failure, which I believe constitutes a significant safety hazard due to the potential for sudden engine failure and loss of vehicle power while driving. As an owner of a 2019 Audi S5, I have experienced symptoms related to this defect, and I urge the NHTSA to investigate this matter to prevent potential accidents, injuries, or fatalities.
Upon starting the vehicle while parked on 10/18/2025, dashboard displayed warning: "turn off engine and check coolant level. See owner's manual. " visual inspection revealed coolant residue on mechanical coolant pump switching valve n649 on cylinder head bank 1, indicating water pump internal seal failure allowing coolant to leak into vacuum control system. Component failed: water pump (ea839 3. 0t engine) - vacuum-actuated design with internal seal failure. Component available for inspection. Safety risk: this documented design defect in ea839 engines can cause sudden drivetrain malfunction and loss of power while driving. While discovered parked in this instance, the same failure mode has caused p0299 codes (turbo under-boost) and "drivetrain malfunction" warnings in other vehicles, creating dangerous loss of power situations. Dealer confirmation: not yet inspected by dealer. Pending diagnostic appointment. Warning symptoms: dashboard coolant warning message was first indication of problem. No prior symptoms observed. Known defect: this is a widespread issue affecting 2018-2024 Audi models with ea839 2. 9t/3. 0t engines (s4, S5, rs5, sq5, a6, a7, s6, s7, a8, q7, q8). Audi has issued technical service bulletins mc-10245526-0001 and mc-10172894-0001 acknowledging coolant pump leak issues. No recall has been issued despite documented failures across multiple model years.
Water pump failure due to coolant migration.