2021 Mazda MAZDA3 engine problems
18 owner complaints filed with NHTSA name the engine on the 2021 Mazda MAZDA3 — 37% of all complaints for this model year.
What owners report
“Spontaneous loss of power while driving on highway. Check engine light came on. Speed limited by car. Continues to vibrate especially at idle from cold start. Code P0304 intermittently popping up.”
filed Apr 23, 2025
“The thermostat malfunctioned on this vehicle, resulting in the thermostat remaining open and providing excess coolant to the engine, which in turn damaged internal components of the engine (compromises safety), decreased fuel economy, increased emissions (compromised safety), and decreased the life…”
filed Feb 21, 2025
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
This Service Alert supersedes the previously issued SAs listed below. The changes are noted in Red text. SA-017/25 12/16/25, 09/08/25, 07/14/25, 05/15/25 and 03/21/25 DESCRIPTION Mazda Connect Frequently Asked Questions…
SA-042-26 · Service Bulletin/Repair Instructions · issued Jul 1, 2026
Engine problems in other MAZDA3 years
| Year | Reports | Share |
|---|---|---|
| 2022 MAZDA3 | 2 | 9% |
| 2020 MAZDA3 | 1 | 3% |
| 2019 MAZDA3 | 11 | 15% |
| 2018 MAZDA3 | 12 | 11% |
| 2017 MAZDA3 | 5 | 6% |
| 2016 MAZDA3 | 7 | 7% |
| 2015 MAZDA3 | 6 | 5% |
| 2014 MAZDA3 | 13 | 9% |
| 2013 MAZDA3 | 11 | 9% |
| 2012 MAZDA3 | 32 | 14% |
| 2011 MAZDA3 | 3 | 2% |
| 2010 MAZDA3 | 22 | 3% |
Other reported problem areas on the 2021 Mazda MAZDA3
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.