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.
2018 mazda Mazda6 engine problems
moderate 20 complaints filed with NHTSA · avg repair $3,100
Complaints
20
Recalls
0
Crashes
0
Avg fix
$3,100
What owners are reporting 7 most recent
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.
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 …
Cracked Cylinder Head. At 50,400 miles. This is far too common of a problem for such a new car with so few miles. I have seen many similar reports online. My mechanic was baffled. This is a $5k cost AT LEAST. Mazda has a history of not covering these defects. And it IS a defect, not a simple wear and tear issue. A cracked cylinder head can eventually lead to engine failure, so it is dangerous to…
The contact owns a 2018 Mazda 6. The contact stated that while merging onto a freeway the vehicle did not accelerate while pressing the accelerator pedal, lost automotive power. After turning the engine off and back on the vehicle operated as normal but later while driving approximately 65 MPH the failure had reoccurred while attempting the pass a semi-truck on the freeway. The check engine warnin…
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 afterwar…
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.
Common questions
How serious is the engine problem on the 2018 mazda Mazda6?
It's a documented issue but not catastrophic. 20 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Other problem areas on this vehicle
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Severity ratings are derived from reported crashes, fires, injuries, and fatalities.
Repair cost estimates are independent-shop national averages and may differ in your area.
Some links on this page are affiliate links.