2018 Mazda MAZDA6 Problems

What owners report

Owners of this model year most often describe a cracked cylinder head that leaks coolant or oil, with some reporting overheating and smoke from the engine area. Other complaints describe the engine stalling or losing power, often with little warning, and some describe fuel pump recall repairs held up because the part was not available. Where mileage is stated, the cylinder head complaints fall between about 47,000 and 80,000 miles, and filings continue into 2026.

1. 1
   Engine

   Cracked cylinder head causing coolant leaks

   • 13 complaints (22%)
   • typically at 6.5 yrs old
   • filed 2022–2026

   Owners describe a cracked cylinder head that leaks coolant, often with the engine running hot or a temperature warning on the dash. Some say the dealer confirmed the crack and quoted a head or engine replacement, and some report overheating, including a case where the car could not move forward on a freeway. Several owners say they were asked to pay, and some accounts describe the repair as normal wear or as outside the warranty or mileage limit. Where mileage is given, these reports run from about 68,000 to 80,000 miles, and many complaints do not state mileage.

   What to check: Ask whether any cylinder head, coolant or thermostat repair has been done and request the paperwork. Check the coolant level over several days and look for coolant or oil residue around the cylinder head and exhaust manifold.

   2 excerpts from owner complaints in NHTSA records

   “Just noticed my coolant was leaking underneath my car and i went to mazda to check and it came out being a cracked cylinder the car are driven by my daughter from school to work only and has 68k miles, mazda doesn’t want to fix because supposedly the engine warranty only last until 60k”

   NHTSA complaint #11519366, filed 2023-04

   “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.”

   NHTSA complaint #11581010, filed 2024-04
2. 2
   Engine

   Sudden stalling or loss of power while driving

   • 15 complaints (26%)
   • median 11,000 mi at 2.0 yrs old (5 state mileage, few)
   • filed 2019–2026

   Owners describe the engine shutting off or losing power with little warning, sometimes in traffic, at a traffic light, or while merging or passing on a freeway. Some cars would not restart for a while, and some complaints mention warning lights before the shutdown; a complaint with transmission fault codes describes a similar sudden loss of drive. Dealers reportedly could not find the reason in some visits, and some owners say the problem returned after an earlier recall repair. Mileage is given in only a few reports, from about 3,200 to 67,000 miles, and several happened in traffic or while merging.

   Recall 19V497000

   What to check: Ask whether any warning lights were recorded during the shutdowns and request the dealer's scan results from each visit. Ask the dealer to confirm by VIN whether the powertrain control module software recall for engine stall has been completed.

   2 excerpts from owner complaints in NHTSA records

   “Vehixle has open recall #3719f. Took vehicle in for service on july 15 and according to NHTSA recall has even out since june 27.2019. To this day I have not gotten any letter or anything stating car has open recall when the car can turn of randomly. Will be taking car in on 08/26/19 but I'm concerned as to why this has not been addressed in any letters or emails”

   NHTSA complaint #11246313, filed 2019-08, 7,200 miles

   “I got this car in may of 2019 so the car is still new and ever since I purchased the vehicle I've been having issues with it first were the calipers sticking and Mazda gave me a hard time to repair the issue after the fact knowing that it was a manufacturing isssue and still tried to charge me I took my vehicle there more then 15 times just to deal things going bad in my car. …”

   NHTSA complaint #11311402, filed 2020-02, 11,000 miles
3. 3
   Engine

   Oil leak onto hot exhaust from cylinder head

   • 9 complaints (16%)
   • median 75,000 mi at 7.5 yrs old (1 states mileage, few)
   • filed 2023–2026

   Owners describe oil dripping from the engine onto the hot exhaust manifold, often with smoke or a burning oil smell under the hood or in the cabin. The leak was often traced by the dealer to a cracked cylinder head, and some owners say a low oil warning came on as the level dropped between changes. Owners describe this as a fire risk, and a complaint says the manufacturer recommended against driving the car. Where mileage is given, these reports cover about 47,000 to 74,000 miles, and some leaks were found shortly after buying a used car.

   What to check: Look for oil on the back of the engine and around the exhaust manifold, and check for a burning oil smell after a drive. Ask the dealer whether the cylinder head was inspected and whether any warranty extension applies to an oil leak, since some complaints say the extension covered only coolant leaks.

   2 excerpts from owner complaints in NHTSA records

   “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 directly onto the exhaust components. …”

   NHTSA complaint #11709431, filed 2026-01

   “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. …”

   NHTSA complaint #11659983, filed 2025-05
4. 4
   Fuel system

   Fuel pump problems and recall repair delays

   • 5 complaints (9%)
   • median 49,000 mi at 4.1 yrs old (3 state mileage, few)
   • filed 2022–2026

   Owners describe a fuel pump recall where the dealer said the repair part was not yet available, and some feel the wait went on too long. A complaint describes hesitation at low speeds when pressing the accelerator, and a separate complaint describes a fuel leak that the dealer traced to rust on the fuel tank top and pump mounting bolts, with both the tank and pump replaced. Where mileage is given, these reports fall between about 27,000 and 75,000 miles.

   Recall 21V875000

   What to check: Ask the dealer to confirm by VIN whether the fuel pump recall has been completed and request the record. Check for any fuel odor and look for rust on the fuel tank area and pump mounting bolts.

   2 excerpts from owner complaints in NHTSA records

   “The contact owns a 2018 Mazda Mazda6. The contact stated upon taken the vehicle to the dealer for an oil change, the dealer notified the contact of a fuel leak. The dealer diagnosed the vehicle and informed the contact that the top of the fuel tank and bolts connected to the fuel pump were significantly rusted, causing the fuel leak. The dealer determined that the fuel tank and the fuel pump needed to be replaced. The vehicle was repaired. …”

   NHTSA complaint #11660947, filed 2025-05, 75,000 miles

   “The contact owns a 2018 Mazda Mazda6. The contact stated that while driving at low speeds, the vehicle would hesitate upon the depression of the accelerator pedal without warning. The contact then received notification of NHTSA Campaign Number: 21V875000 (Fuel System, Gasoline) however, the part to do the recall repair was unavailable. The dealer was also notified about the recall; however, the contact was informed that the parts were not yet available. The manufacturer had been notified of the recall. …”

   NHTSA complaint #11448661, filed 2022-01, 27,000 miles

Buying note. Buyers considering this model year may want a pre-purchase inspection that checks the cylinder head, coolant and oil leaks, and engine temperature behavior. They can also ask the dealer to confirm by VIN whether the fuel pump recall and any other open recalls have been completed.

Summary written with AI from a sample of 51 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.