10.0

really awful
Crashes / Fires:
0 / 1
Injuries / Deaths:
0 / 0
Average Mileage:
3,225 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2018 Mazda MAZDA6 engine problems

engine problem

Find something helpful? Spread the word.
Get notified about new defects, investigations, recalls & lawsuits for the 2018 Mazda MAZDA6:

Unsubscribe any time. We don't sell/share your email.

2018 Mazda MAZDA6 Owner Comments (Page 1 of 2)

problem #24

Dec 102023

MAZDA6

  • miles

A D V E R T I S E M E N T S

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

- Benton, KY, USA

problem #23

Dec 222024

MAZDA6

  • miles
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.

- Lafayette, NJ, USA

problem #22

Nov 182024

MAZDA6

  • miles
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.

- Harvey Cedars, NJ, USA

problem #21

Sep 282024

MAZDA6

  • miles

A D V E R T I S E M E N T S

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

- Denver, CO, USA

problem #20

Sep 112024

MAZDA6

  • miles
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 drive with it. The problem HAS been confirmed by an independent service center. I got a oil pressure warning sign.

- Kansas City, MO, USA

problem #19

Jul 082024

MAZDA6

  • 67,000 miles
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 warning light had also illuminated and the vehicle was eventually towed to the local dealer who was unable to determine the cause of the failure. The vehicle was not yet repaired. The manufacturer was not yet contacted. The failure mileage was 67,000.

- Carlsbad, CA, USA

problem #18

Jul 082024

MAZDA6

  • miles

A D V E R T I S E M E N T S

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.

- Louisa, VA, USA

problem #17

Apr 032024

MAZDA6

  • miles
Start engine when cold and it knocks/ taps from the valve cover very loud, found a tab for valve lifters. Mazda said I-??m out of warranty and it would be a 2k fix on a car I just bought second hand. A lot of other drivers have experienced the same issue and have even said it-??s a safety issues as when it happens for long enough it could cause the cams to wear down causing the car to stall out in traffic or in a dangerous road situation. Very dangerous imo and should be fixed for free as Mazda admitted that it-??s a design flaw of the HLA

- Cary, NC, USA

problem #16

Mar 222024

MAZDA6

  • miles
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.

- Laurel , MD, USA

problem #15

Mar 222024

MAZDA6

  • miles
Mazda has a huge issue with there HLAs hydraulic lash adjusters. I've driven the car for 60k+ miles and it's ticked every since I got the car. And many people in the community also have the issue. And Mazda says it's fine and to rev the car above 3k rpms. This issue needs to be resolved. Before my warranty went up they said they'd fix it at the dealer if it would tick while in there possession. That's just not reasonable the tick happened as random as it gets. Please please for the sake of Mazda and all it's owners make Mazda fix this as a recall. Many people in the US would be the happiest people in the planet not having to hear there 20k$ car tick like a broken old piece of junk. Thank you for listening. Your truly a franticly hopeless hard working america with a half broken car.

- Marquette , NE, USA

problem #14

Mar 072024

MAZDA6

  • miles

A D V E R T I S E M E N T S

At 65,000 miles and on time maintenance a head gasket blew.

- Thibodaux, LA, USA

problem #13

Dec 042023

MAZDA6

  • miles
The engine has developed an oil leak that is a known manufacturing defect of Mazda 2.5 litre engines TSB #SA-031-21. The oil drips on the hot exhaust and sends smoke into the cabin and probably could start a fire. Also if the engine runs out of oil, it will cause the car to shut off and stall in traffic.

- Fairport , NY, USA

problem #12

Dec 042023

MAZDA6

  • miles
Cracked Head, not caused by anything I did.

- Itasca, TX, USA

problem #11

Dec 132023

MAZDA6

  • miles
Was at a drive in window and car turned off and couldn't restart. Windows and lights would work but car wouldn't restart. Could of been driving and would of crashed. Had 3 people family in car. It was 9 pm had to have towed to nearest auto mechanic place $150. They are diagnosing and that is $186. This is a scary thing and going to BBB and filing a complaint I'm mad as he'll. Have had inspection done on this car 2 months ago and all required services to this car. This was without warning which is horrifying.

- Herndon, VA, USA

problem #10

Sep 292023

MAZDA6

  • miles
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.

- Leander, TX, USA

problem #9

May 142023

MAZDA6

  • miles
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.

- Hiram , GA, USA

problem #8

Apr 162023

MAZDA6

  • miles
Due to design issues, the engine cylinder head became cracked after normal everyday usage. Coolant began to leak badly and car engine became hot while driving.

- Raleigh, NC, USA

problem #7

Apr 272023

MAZDA6

  • miles
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

- Katy, TX, USA

problem #6

Apr 262023

MAZDA6

  • miles
Mazda is producing and installing bad belt tensioner sand bad belts for new cars belt tensioner only lasts about 27,500 miles and belt only lasts 11 month/14,000 miles belt tensioner is a major safety issue

- Bellfower , CA, USA

problem #5

Jun 282022

MAZDA6

  • miles
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.

- Gaithersburg, MD, USA

Read the next 4 complaints »

Not what you are looking for?