2018 Mazda MAZDA6 engine problems

Related recalls

• Recall 19V497000Jun 27, 2019262,220 vehicles
  ENGINE · POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)

  Mazda North American Operations (Mazda) is recalling certain 2018-2019 CX-5, Mazda6, and 2019 Mazda3 vehicles. A software error in the powertrain control module (PCM) may cause the engine to stall.

  Risk: An unexpected stall increases the risk of a crash.

  Remedy: Mazda will notify owners, and dealers will reprogram the PCM software, free of charge. The recall began August 20, 2019. Owners may contact Mazda customer service at 1-800-222-5500, option 4. Mazda's number for this recall is 3719F.

What owners say

1. Filed Aug 7, 2026VAEngine

   The car only has 70k miles on it. The engine started smoking under the hood. Immediately stopped to look. There was oil leaking but I could not see from where. I took it across the street to the Toyota dealership and had them look at it. They explained to me that there was a crack in the cylinder head and oil was leaking everywhere. Potentially causing a fire or even an explosion. The old was leaking all over the exhaust manifold and engine. I had my 2 toddlers in the car…

   NHTSA complaint #11755535 · source
2. Filed Apr 30, 2026CAEngine

   Crack in Cylinder Head of engine. Mazda has been sued about this and have issued recalls on turbo engines, but not on non turbo ones though its the same systemic design issue with these engines. Wants me to pay 5-7k out of pocket.

   NHTSA complaint #11734993 · source
3. Filed Apr 22, 2026NJEngine

   My cylinder head is leaking coolant. There is a well known and well documented issue with these cylinder heads cracking due to poor casting. This has become such a big issue that Mazda has even recalled the cylinder heads, BUT, only if the engine is equipped with Turbo. However, this issue is becoming enormous even for non turbo owners and is a huge safety issue as it can lead to overheating, stalling, and further damage to other components. I feel very strongly that it is…

   NHTSA complaint #11733118 · source
4. Filed Apr 7, 2026CAEngine

   Car had a coolant leak due to cracked cylinder head that was defective from the factory it was fixed but now the car has engine problems again. Don’t want to keep having these issues in the future

   NHTSA complaint #11729758 · source
5. Filed Feb 22, 2026PAEngine

   Per Mazda inspection, the back side of cylinder head #3 has an oil leak which is leaking onto the exhaust manifold. This creates a direct fire hazard as Mazda said they highly recommend not driving it for that reason. The Mazda dealership inspected and confirmed the issue, it in February 2026, with only 74,000 miles on the vehicle.

   NHTSA complaint #11719756 · source
6. Filed Jan 7, 2026SCEngineTransmission & Drivetrain

   I recently discovered a significant oil leak near the exhaust manifold of my 2018 Mazda 6 (2.5L NA), which has resulted in visible smoke and a burning oil odor. Upon taking the vehicle to the nearest Mazda dealership for a diagnosis, the service department informed me that the vehicle has suffered a cracked cylinder head. An active oil drip is visible behind the engine near the exhaust manifold immediately upon starting the car; consequently, the engine is leaking oil…

   NHTSA complaint #11709431 · source
7. Filed Oct 17, 2025OHEngine

   Cracked cylinder head causing oil leak and possible coolant leak. This is a known issue with this year and model. Mazda is trying to suggest the issue is only for the turbo engine, but the non-turbo engine is also defective, per countless reports online. I have a video from the service technician from the mazda dealership, but it is too big to upload.

   NHTSA complaint #11694210 · source
8. Filed May 9, 2025GAEngine

   Bought used with 47k miles. Two weeks later, took it to my mechanic for an inspection, they found a massive oil leak on the back of the motor. Took it back to the dealership and they diagnosed it as a cracked cylinder head, for which there is a known TSB and warranty extension. Unfortunately, the warranty extension only covers a coolant leak from the cracked cylinder head, not an oil leak. Thankfully, the dealership took care of me but had they not, I was looking at a $7k+…

   NHTSA complaint #11659983 · source
9. Filed Jan 8, 2025KYEngineOther / Unknown

   Coolant leaks at the cylinder head around the exhaust manifold causing my car to over heat. Also when my thermostat is set to the exact temperature for both sides my driver side blows cold and the passenger side blows hot

   NHTSA complaint #11634788 · source
10. Filed Jan 4, 2025NJEngine

    Driving in traffic and the engine temperature warning appeared on dash. Dealer has confirmed there is a large coolant leak from the cylinder head. Mazda released a technical service bulletin regarding the issue affecting Mazda6, cx-5 and cx-9, but I will have to pay for a head gasket replacement.

    NHTSA complaint #11634029 · source
11. Filed Nov 26, 2024NJEngine

    Cracked cylinder head near the exhaust manifold. Created a large oil leak. Oil on the exhaust is a fire hazard. After one quart of oil loss a low oil level light comes on. This is a reported problem. One version of the engine I have has a Mazda TSB and an extended warranty. TSB 01-0022/23 A local repair shop has diagnosed the problem.

    NHTSA complaint #11627463 · source
12. Filed Sep 28, 2024COEngineFuel, Hybrid & EV PropulsionOther / Unknown

    My car has stalled out on me 6 times in traffic and wouldn’t restart for hours. I took it to the Mazda dealership and they told me nothing was wrong but it continues to happen. I need something done as soon as possible

    NHTSA complaint #11616978 · source

Source: U.S. National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation public data. Complaints are submitted by owners and are not verified by NHTSA or by us; a complaint does not prove a defect exists. View this vehicle on NHTSA.gov Methodology