2019 AUDI S5 Problems & Complaints

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.

Our gas tank fuel level sensor is faulty so we can no longer tell how much gas is in our car. The check engine and fuel light are permanently on. This fuel sensor malfunction caused me to run out of gas in the middle of the road. The only way to fix it is to replace the entire gas tank at great expense. We were quoted $3500-$4000. We only have 44K miles on the vehicle.

THE TIRE PRESSURE MONITORING SYSTEM (TPMS) DID NOT FUNCTION AS REQUIRED, AND PRESSURE WAS DANGEROUSLY LOW WHICH SIGNIFICANTLY DAMAGED THE TIRES OVER A VERY SHORT PERIOD OF TIME (2-6 WEEKS). I AM CONCERNED GOING FORWARD IF THE TPMS UTILIZED ON THE S5 DOES NOT FUNCTION AS SHOULD BE EXPECTED PER FEDERAL REGULATIONS. PER 49 CFR 571.138 WHEN PRESSURE OF 1 TIRE UP TO 4 TIRES IS < 25% BELOW COLD INFLATION PRESSURE, A LOW PRESSURE WARNING SHOULD ILLUMINATE AND REMAIN ILLUMINATED. THE TPMS SHOULD HAVE PROVIDED AN ALERT WHEN ONE OR MORE OF MY TIRES WAS AROUND 30 PSI, YET ALL GOT TO UNDER 24 PSI WITH NO WARNING. THE AUDI SERVICE ADVISOR EXPLAINED THAT THE TPMS UTILIZED ON THE S5 IS AN INDIRECT SYSTEM THAT DETECTS CHANGE IN SPEED/CIRCUMFERENCE FOR AN INDIVIDUAL TIRE THAT WOULD INDICATE LOWER PRESSURE, AND IT WILL NOT ALERT IF PRESSURE IN ALL 4 TIRES DECREASES SIMULTANEOUSLY. THIS IS A KNOWN ISSUE, YET AUDI INSISTS THERE IS NO PROBLEM WITH THE SYSTEM FUNCTIONING LIKE THIS. THE OEM TIRES ON THIS VEHICLE ARE VERY LOW PROFILE AND LARGE DECREASE IN PRESSURE IS NOT OBVIOUS FROM VISUAL INSPECTION. SIGNIFICANT PRESSURE REDUCTION OCCURRED MORE RAPIDLY WITH THIS VEHICLE THAN ANY SIMILAR VEHICLES I HAVE OWNED, SO A TPMS THAT CANNOT BE RELIED UPON IS A MAJOR SAFETY CONCERN.