2018 Mazda MAZDA6: engine overheating

Filed Apr 22, 2026 · Engine · NJ

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 time for Mazda to take some responsibility and extend the cylinder head recall to the non turbo engines.

Filed Apr 7, 2026 · Engine · CA

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

Filed Oct 17, 2025 · Engine · OH

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.

Filed May 9, 2025 · Engine · GA

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+ repair on a car I had owned for 2 weeks. In the TSB, Mazda acknowledges that there were both design and manufacturing flaws for the affected model years. In acknowledging the issue, they should have issued a recall for affected vehicles, not a simple warranty extension

Filed Jan 8, 2025 · Engine · KY

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

Filed Jan 4, 2025 · Engine · NJ

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.

Filed Jul 9, 2024 · Engine · VA

At less than 95,000 miles, the car suddenly started overheating. Coolant level was fine, maybe ever so slightly low (could still see the coolant in tubing and some in reservoir, which was closer to low than full). Replaced ECT sensor, thermostat and water pump which seemed to fix the issue. Drove for 9-10 days with no issues and it started overheating again. I was able to park quickly afterward at work (<10 seconds). Schedule for drop off at dealer (if car didn't show signs of overheating first (would have called tow truck). Checked fluid levels in car (was ~1Qt low) and topped it off. Drove to dealer (~30min ride) with no issues whatsoever. When dealer looked at it, they said cylinder was warped and leaking, requiring new engine. A just paid off car, with less than 100k miles on it, now needs a new engine that will cost more than half of what it's worth.

Filed Apr 3, 2024 · Engine, Transmission · MD

Noticed slight coolant leak, took car to mechanic, he stated cylinder head was cracked, & causing coolant to spray everywhere. Towed car to dealer. Was given repair estimate of over $11,000, for a new engine. I see a safety bulletin online for my year make & model car. This overheating can apparently cause an engine fire. So far, Mazda seems to be showing negligence & not properly addressing the issue for owners.

Filed Oct 3, 2023 · Engine · TX

Coolant leaking from head, informed by dealer the cylinder head is cracked and the entire engine needs to be replaced. The engine has just hit 80k miles at this point. This issue caused multiple instances of overheating while driving, one of which caused the vehicle to fail to move forward while on an elevated freeway overpass with no shoulder during rush hour. This issue appears to be widespread for 2016 and newer Mazda models with the 2.5L turbo engine.

Filed Jul 3, 2023 · Engine · GA

I was driving my car, it overheated. I took it in and was told it needs a new engine. I was told it was not fault of my own why it overheated. It had 2 oil leaks and a blown head gasket.

Filed Jun 28, 2022 · Engine · MD

Took care for routine maintenance to car dealer (Ourisman Mazda Rockville MD). No problems with car. They reported that I had an 'Coolant Leak at the Cylinder Head'. Cost to fix: $6412.47 They reported that it was 'normal wear and tear'. I found a service bulletin from Mazda whereby they admit a manufacturing defect that affected 2.5T engines. They corrected on March 25th, 2021. However, engines prior to this date had this defect. No recalls were created. No warning to owners. My car was within the mileage warranty when they identified the defect (<60k miles and < 5 yrs old). While my car is less than 5 years old, they now identified the leak, but it has over 60k miles. The local dealer said I was out of warranty and there is nothing they could do. I spoke with Mazda North American Operation and reported the Technical Service Bulletin that they put out on 10/15/21 (after they had already identified the problem, re-engineered the engine, and changed the manufacturing line), I also explained what was reported to me by Ourisman Mazda and emailed her all the documents. She reported that she would be getting back to me in 24-48 hrs.