Huge win for car owners! All TSBs to be made public. The Center for Auto Safety just made the NHTSA (US Government) make public the full text of all TSBs from now on. They are the same organization that has petitioned the NHTSA & filed lawsuits to protect car owners over exploding gas tanks & other major safety issues. Whenever you drive in your car, you are safer thanks in part to a lot of work over the years by this small but very effective consumer advocacy group.

Please take a moment & say thank you by donating $5 or whatever you can to the Center for Auto Safety.


really awful
Crashes / Fires:
0 / 1
Injuries / Deaths:
1 / 0
Average Mileage:
66,776 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.

2004 Mazda MAZDA6 engine problems

engine problem

Find something helpful? Spread the word.
Get notified about new defects, investigations, recalls & lawsuits for the 2004 Mazda MAZDA6:

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

2004 Mazda MAZDA6 Owner Comments

problem #6

Apr 262016


  • 40,000 miles


The V6 motor in my Mazda 6S has been leaking oil for almost 10 of the 12 years I've owned it. The oil leaks out of the faulty seals on the timing chain cover in front of the passenger, and the oil drops onto the catalytic converter. This oil vaporizes and that vapor enters the cabin in slow speed driving and when stopped at intersections. I complained about a burning oil smell many times while the car was still under warranty, and the Mazda service techs always pretended like they didn't find any problem. Years down the road, I am finding this is a rampant problem with all Ford and Mazda cars and SUVS with this "duratec" 3.0 V6 which was made by Ford. It is installed in many Ford, Mercury and Mazda vehicles. I carry a fire extinguisher with me in the event I have an under hood fire, and I'm very worried about my health after all these years of breathing this vapor. The cost to repair this seal failure is daunting. I hope mhtsa can see that Ford has been covering up this defect, endangering lives and the health of drivers as well as creating a tough financial burden on the owners to fix the issue. I gave a date on the form below, since it was required, but this has been going on since 2006 or so.

- Hanover, MA, USA

problem #5

Mar 142016


  • 115,000 miles
The contact owns a 2004 Mazda 6. while driving 30 mph, the vehicle stalled without warning. The vehicle was towed to an independent mechanic and the battery was replaced, but the failure recurred. The vehicle was towed to a dealer where it was diagnosed that the oil needed to be changed and the starter needed to be replaced. The vehicle was repaired. After the vehicle was serviced and while driving at an unknown speed, an abnormal sound emitted from under the hood and the check oil warning light illuminated and the vehicle stalled. The vehicle was taken back to the dealer where it was diagnosed that there was metal fragments in the oil and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 115,000.

- Birmingham, AL, USA

problem #4

Dec 302015


  • miles
The contact owns a 2004 Mazda 6. while driving at an unknown speed, the contact smelled a burning odor and noticed white smoke coming from the hood of the vehicle and inside the vehicle. The contact turned off the engine and the smoke disappeared. The vehicle was towed to a dealer where it was diagnosed that the engine burned out and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The VIN and failure mileage were unknown.

- Birmingham, AL, USA

problem #3

Oct 012014


  • 139,000 miles


Engine started knocking out of no where really lost power it spun the bearing and rod in the engine its the 2.3 liter engine Mazda has had several complaints about this from 2004 to 2006 I have several people that have had the same issue like I said could cause major accidents it was not low on oil and was not ready for its maintenance Mazda needs to be held accountable for this.

- Pueblo, CO, USA

problem #2

Mar 162006

MAZDA6 6-cyl

  • 30,000 miles
Re: Mazda 6 V6 made in the Ford/Mazda auto alliance factory in flat rock, mi. The miles/speed I listed are actually N/a - this is an ongoing problem that has existed for most of the 10 years I've owned this car. I complained about smelling burning oil coming into the car's cabin since the car was only 1 year old, but the Mazda repair techs appeared to "never notice the smell". it was more than a year or so after my warranty ended - despite a dozen instances of complaining to Mazda dealers of this smell - that I realized my problem was oil leaking from my V6 motor's timing chain cover. The oil leaks down the side & bottom of the motor & drips (only while driving, never while resting) onto the top of one of the exhaust system's catalytic converters. The intense heat of the converter vaporizes the oil, the result of which enters the car's cabin through the HVAC system. I have been adding a quart of oil almost every two months for years now, breathing this carcinogenic vapor and worrying about an engine fire for the better part of a decade now. Leading up to discovering the leak, I had replaced my valve cover gaskets & oil pan & gaskets at great cost. The proper repair for this would likely require removing my car's engine & a 12 hour repair at $100 per hour, and that's just the labor. When researching this problem, it appears in online forums to be a consistent problem for hundreds (likely thousands) of owners, and variations of this Ford-made V6 engine are installed in a dozen Ford and Mazda cars. I firmly believe that over the years Ford - knowing this was a consistent problem - advised it's dealer network to keep hush-hush and pretend to not understand or notice the problem in an effort to avoid a costly recall campaign. I feel that the time has come for Ford, not Mazda, to pay the piper, and I would like my car repaired without a financial hardship placed upon me.

- Hanover, MA, USA

problem #1

Feb 272014


  • 76,654 miles
The way the catalytic converter is designed on cylinders 1, 3, and5 it gets clogged but buy than your rings and bearing have overheated destroying your engine with in a thousand miles of replacing the catalytic converter you find this out. I was driving home the engine was at normal temp driving fine.. than the car would not go over five mph. Had it towed to the local grage. 1 of the catalytic converters was clogged on cylinders 1, 3 and, 5 had it replaced plus and oil change. Car worked fine for about a week and half than a loud tick and knock started next day had it looked at my oil was gray and you could see the blow buy when the engine was running. Tore into the engine a bit and bearing where destroyed. I was told I'm not the first person this haloed to. And after researing this online I found a lot of other people that this also happens to.

- Torrington, CT, USA

Not what you are looking for?