There are 3 owner-reported engine complaints for the 2012 Toyota Siennain NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Coolant leaking from rear of the engine through the head gasket. Vehicle struggles to accelerate beyond 55mph or 80kmph. A quick search on the internet shows that this is a frequent occurrence in this 3.5L V6 engine from Toyota model years 2011 through 2017.
TL* THE CONTACT OWNS A 2012 TOYOTA SIENNA. WHILE DRIVING VARIOUS SPEEDS, A KNOCKING NOISE WAS PRESENT COMING FROM THE ENGINE. THE CAUSE OF THE FAILURE WAS NOT DETERMINED. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE VIN WAS NOT AVAILABLE. THE FAILURE MILEAGE WAS 70,000.
TL* THE CONTACT OWNS A 2012 TOYOTA SIENNA. THE CONTACT STATED THAT WHILE DRIVING 75 MPH, THE VEHICLE STALLED WITHOUT WARNING. THERE WAS NO BRAKING POWER AND AS THE CONTACT ATTEMPTED TO GUIDE THE VEHICLE OFF THE ROADWAY, HE CRASHED INTO A CURB. THE HORN THEN BEGAN TO SOUND AS SMOKE FILLED THE INTERIOR CABIN. THE SIX OCCUPANTS OF THE VEHICLE BECAME TRAPPED INSIDE AND WERE ABLE TO CLIMB OUT OF A PARTIALLY OPENED WINDOW AS THE VEHICLE BECAME ENGULFED IN FLAMES WITHIN MINUTES. THE VEHICLE WAS DESTROYED, THERE WERE NO INJURIES AND A POLICE REPORT WAS NOT FILED. THE VEHICLE WAS NOT INSPECTED TO DETERMINE THE CAUSE OF THE FAILURE OR THE FIRE. THE FAILURE AND CURRENT MILEAGE WAS 23,000.
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