There are 1 owner-reported engine complaints for the 2011 Audi S4in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
THERE IS A WELL KNOWN ISSUE WITH THE AUDI 3.OT ENGINE'S PLASTIC THERMOSTAT FAILING! I WAS DRIVING AND THE THERMOSTAT FAILED CAUSING THE ENGINE TEMP TO SKYROCKET TO "H"! I DROVE HOME BECAUSE I WAS CLOSE ENOUGH WITH THE HEATER ON HIGH. THEY FLATBEDED MY CAR ON 9/29/14 FROM MY DRIVEWAY TO THE AUDI DEALERSHIP. DEALERSHIP DETERMINED IT WAS A FAILED THERMOSTAT AND REPLACED IT WITH ANOTHER "PLASTIC THEMOSTAT." THE SECOND THERMOSTAT FAILED 2 DAYS LATER. I JUST TOOK THE CAR TO THE AUDI DEALERSHIP AGAIN THIS MORNING 10/3/14 TO HAVE IT REPLACED AGAIN! THIS PART NEEDS REENGINEERED BECAUSE ITS PLASTIC AND WILL FAIL AT SOME POINT. THANK GOD I WASNT OUT OF STATE WITH MY FAMILY AND IT FAILED BECAUSE I WOULD HAVE BEEN STRANDED! *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026