2016 Toyota Tacoma & 2014 Mazda6 diesel decisions now make sense

Both Toyota and Mazda have fans that want diesel engines in their cars. Toyota Tacoma fans want the diesel so they can tow large-truck loads in their mid-size pickup while getting improved fuel efficiency. Mazda6 fans want the engine so they can have a fuel-sipping sedan with great torque. Both companies opted not to go with diesels after serious consideration and that decision is looking smarter every day.

As far back as 2012 Torque News began reporting the news that the Mazda6 sedan’s new U.S. market generation might have a diesel engine option. In November of 2014, Mazda confirmed it would sell its diesel Mazda6 in the U.S. market. Jim O'Sullivan, president and CEO, Mazda North American Operations said Mazda was planning a diesel option for its Mazda6. He told the press, "… we couldn't be more excited to officially introduce North America to our latest next-generation product, the 2014 Mazda6, as well as showcase even more engineering accomplishments under our SkyActiv technology umbrella with the SKYACTIV-D clean diesel engine…The best is yet come." However, it never did come to the U.S.

Mazda abruptly changed its mind in January of 2014. The new diesel engines did go into Mazda6 cars in other markets, and Mazda races the diesel Mazda6, but the company pulled the engine just before launch in the U.S. Mazda never did say exactly why the diesel was pulled, offering only that “it was decided that further development is required to deliver the right balance between fuel economy and Mazda-appropriate driving performance.” Our speculation was that when tuned to meet EPA emissions requirements, there was no real-life performance or fuel economy gains in comparison to the gasoline Mazda6.

We asked Mazda today if there were any plans to ever bring a diesel to the U.S. and were pleasantly surprised by the upbeat rely. Mazda said "Mazda remains committed to bringing diesel to the U.S. We want to make sure the diesel's performance is up to the standards which are expected when driving any Mazda vehicle. Once we are satisfied that we can deliver the right balance between fuel economy and Mazda-appropriate driving performance we will bring our SKYACTIV diesel engine to the United States."

Toyota was much more blunt about why diesels don’t work. Although popular all over the world, Toyota diesel trucks and cars are not sold in the U.S. market where our emissions controls have been more stringent. Europe is now catching up, but for the past decade or so our requirements were tougher. Commenting on the reason that Toyota opted out of the diesel for the Tacoma, chief engineer Mike Sweers said, “The difficulty with the diesel is LEV III [emissions standards]. The difficulty is the cost-to-benefit relationship. Everybody loves diesel in trucks. The downside is the after-treatment systems can add $3,000 or more. …If I develop a diesel system for our country, and I spend a huge amount of money to do that, I won’t see a return on the investment. That’s what we’ve struggled with.”

Mazda and Toyota both discovered that U.S. diesels require very elaborate emissions controls equipment which reduce fuel efficiency and power. There is no way to get around that. Something Volkswagen is now discovering as well.

Related Stories:
How many more Tacomas could Toyota sell if it offered a diesel in the U.S.?
Why can't the 2015 Mazda 6 diesel work in the US?