Six-cylinder engines first powered pre-World War I aircraft long before they gained popularity in the automotive sphere. BMW, a manufacturer with a well-publicized love affair with inline-six engines, built some incredible war and post-war time six-cylinder aviation engines, which later found their eternal home in automobiles. But BMW wasn't the first automaker to use six-cylinder engines in vehicles. Spyker introduced the 60-hp Racer in 1903 with a straight six powerplant. After World War II, the first V6 engine debuted with the Lancia V6 getting featured under the Lancia Aurelia's hood in 1950. So, this engine type has a timeless heritage under its belt.
Updated April 2023: With its efficient compromise of power and economy, six-cylinder engines offer the sweet balance that most gearheads crave in an engine. Its compactness also makes it a perfect fit for a wide range of vehicles, and thanks to its relatively high reliability, V6 has also featured in a wide range of performance vehicles. Hence, we've updated this article with more examples of the most reliable V6 engines ever made.
Six-cylinder engines deploy clever and efficient designs to draw smooth power, and they have been the heart of some of the greatest vehicles of all time. The straight-six and V6 engine configurations have their distinct advantages and disadvantages. There are fewer straight-six engines in new vehicles today since manufacturers seem to prefer turbocharged V6 engines offering V8 performance levels. But, some manufacturers like BMW didn't relent with their inline-sixes, so they both have their place. We've witnessed many incredibly six-cylinder engines over the years, and these are the most reliable of the lot.
11 Ford 300 Inline-Six – Ford F-Series Trucks
The ford 300 straight-six is easily one of the greatest engines ever built. It featured in the legendary Ford F-Series trucks for three decades and proved a trusted workhorse for nation builders, from farmers and construction workers to loggers. It came with a big 560lbs iron block that proved practically unkillable.
The engine has seen plenty of abuse through its application in millions of farm pickups, tractors, wood chippers, irrigation pumps, etc. It rarely broke down; on average, many Ford 300 engines run as much as 300k to 400k miles.
10 Jeep 4.0 Inline-Six – Jeep Cherokee, Wrangler, Wagoneer
Although Jeep engines are still pretty good, they aren't among the most dependable based on third-party reliability reviews. Still, Jeep vehicles have featured some solidly reliable motors in the past, including the Jeep 4.0 inline-six. Jeep built the 4.0 between 1986 and 2006, first by AMC and then by Chrysler after the 1987 takeover.
The Jeep 4.0 powered the Jeep Cherokee, Wrangler, Wagoneer, Jeep Comance, and Grand Cherokee. It didn't put out much power, but its design was simple and provided longevity and reliability. It will keep running long after the rest of the Jeep has rusted away.
9 Jaguar XK6 Inline-Six– Jaguar D-Type, E-Type, XK120
Jaguar built the XK inline-six DOHC engine from 1942 to 1992, and it went on to earn reverence for powering iconic road cars and race cars. It underwent constant evolution and improvement through its 43-year run, coming in five displacements between 2.4 and 4.2 liters. Jaguar deployed the XK6 on some of the fastest cars in its day, including the Jaguar XK120, E-Type, and the Le Mans-winning D-Type.
The XK6 earns praise for its raw power, smooth delivery, and unmistakable soundtrack. These engines were as high-spec and reliable as Jaguar could manage, with claims of some over-engineered aspects.
8 12 Valve Cummins 6BT Inline-Six – Dodge Ram Trucks
The turbocharged 12-valve Cummings 6BT engine is arguably the world's most famous diesel engine. The six-cylinder powerplant first appeared in the 1989 Dodge Ram pickup truck and soon replaced monstrous V8s thanks to its ability to provide massive low-end torque and improve fuel consumption.
The engine gained a cult following thanks to its tremendous performance potential and bulletproof reliability. The cast iron cylinder block and head are impeccably durable, and the rest of the engine is extremely simplistic, operating mostly with mechanical components and few electronics.
7 Chrysler Slant Six Inline-Six – Chrysler Cars, Trucks, And Vans
Chrysler's 170, 198, and 225 Slant Six series was arguably the most durable inline-six engine ever built. They built it between 1960 and 1983 with a deep-skirt block and tall-short pistons, which proved extremely reliable. Its slant nature earned it the popular moniker "leaning tower of power."
The Slant six remains one of the most rugged and reliable powerplants that proved tough to kill, never stopped running or wore out, and rarely needed repairs. It is common to find engines that run hundreds of thousands of miles long after the rest of the car have rotted away.
6 Nissan RB26DETT - Nissan Skyline GT-R32
At the height of the JDM car craze of the late 80s, Nissan produced the RB26DETT straight six, which proved to be one of the most solid power mills out there. It came with 276 hp stock in the early models but can take high abuse levels. It forms a sturdy modification foundation, and many custom examples produce over 1000 ponies. This family of engines powered iconic Skyline cars from the R32 to the R34 GT-Rs.
Many consider the tin turbo RB26DETT an engineering marvel built for high performance. It has proven incredibly durable with good maintenance.
5 3M Inline-Six - Toyota 2000GT
The Toyota M family included cast-iron block engines with aluminum cylinder heads built from the 1960s to the 1990s. It came in four-cylinder, six-cylinder, and eight-cylinder iterations that underwent several evolutions before Toyota rested the series. The 3M naturally inline-six was a special engine built from 1967 to 1971 for the legendary supercar, the Toyota 2000GT. Yamaha took the original M's block and built custom aluminum heads with a hemispherical shape and 79 degrees valves.
Today the 2000GT is one of the most valuable and iconic Japanese cars ever, thanks partly to the durable 3M engine under the hood. It instantly proved its sturdiness when it set thirteen FIA records for endurance and speed after undergoing a 72-hour test at the Yatabe proving ground.
4 Honda J35 V6 – Honda Accord, Odyssey & Ridgeline
Everyone recognizes Honda for its consistent appearance on top of reliability lists. They've built several screaming and bulletproof four-cylinder powerplants alongside dependable V6s like the J-series, the brand's go-to engine in North America. It powers everything from the sporty Honda Accord coupes to the Ridgeline pickups and Odyssey minivans.
The SOHC J35 V6 offers silky smooth power delivery with quick revs and notable VTEC changeovers. Also, it comes with bulletproof reliability, making it one of the greatest V6 engines, which is why it has been going strong since 1996.
3 Honda C30A/C32B V6 – Honda/Acura NSX
The C-Series is yet another notably reliable engine from Honda. It was the brand's first production V6, built in various iterations between 1985 and 2005. The C30A and C32B were the most complex and costly variants, so Honda reserved them for the Honda and Acura NSX sports cars.
While it has nothing exotic by modern standards, Honda's engineers seriously crafted the flagship engine to fit the luxury car V6 status of the mid-engined NSX. The hand-built C32B engine proved a timeless and solidly reliable engine to personify Honda's quality engines.
2 2JZ-GTE Inline-Six – Toyota Supra
Toyota has built some incredible, including the high-revving Lexus LFA's V10, but their 2JZ-GTE inline-six engine found on the A80 Supra is among the most desirable. For over twenty years, the 2JZ proved nearly indestructible. Toyota built it for enthusiasts, making it a legendary powerplant in the tuner community.
It has been subject to some of the most outrageous mods in the automotive world, and some of its applications output as much as 2000 hp without blowing up. Even with moderate upgrades, you can get up to 750 hp from the cast-iron block.
1 BMW M88 Inline-Six – BMW M1, M5
BMW has produced several iconic engines, but the M88 is in a league of its own. First introduced in the M1 sports car as a 3.5-liter inline-six produced from 1978 to 1981, the M88 came in a mid-engine configuration, helping the M1 become BMW’s first mass-produced mid-engine car. With an output of 272 horses, this initial version of the M88 outperformed even some V8s of its era.
Not done with the engine, BMW later modified the engine for a run in the M5, adding a Bosch Motronic fuel injection system for an improved output of 282 horses. Thanks to the improved output, the modified M88 engine powered the M5 to become the world’s best performing sedan of its era, and even beyond.