Mercedes-Benz has long been synonymous with engineering excellence and unparalleled luxury, but it’s the brand’s dedication to reliability that often goes unnoticed.
Behind the opulent interiors and high-tech features lie some of the most robust engines ever built, delivering not just performance but also exceptional durability.
In this article, we shine a spotlight on the eight most reliable Mercedes engines ever made.
These powerhouses have proven themselves over time, setting the benchmark for automotive engineering.
Read on to discover the engines that have helped solidify Mercedes-Benz’s legacy of reliability.
Table of Contents
OM617 Diesel Engine
The OM617 engine holds a special place in Mercedes-Benz history, renowned for its extraordinary reliability. This inline-five diesel powerhouse was produced from 1974 to 1985, originally designed to provide a mix of performance and fuel efficiency. With a displacement of 3.0 liters and turbocharged variants available, it offered a decent balance between power and economy.
Known for its durability, some OM617 engines have clocked over a million miles without major overhauls. Its mechanical simplicity and robust construction contribute to its long-lasting nature. Often found under the hoods of the W123 and W126 series, such as the 300D and 300SD, the engine has also been used in military applications and even boat conversions due to its stout build.
However, no engine is entirely free of faults. Common issues with the OM617 include oil leaks and difficulties in cold-weather starting, both of which are generally considered minor and easily fixable.
M111 Engine
The M111 engine, coming to life in the early 90s, was Mercedes-Benz’s go-to for reliability and solid performance.
This four-cylinder petrol engine, ranging from 1.8L to 2.3L, pumps out 113 to 194 hp, depending on the specific model.
Featuring twin overhead camshafts and a smart multi-valve design, it managed to balance pep with pretty decent fuel economy.
The M111 powered numerous adventures in models like the C-Class, E-Class, and SLK, praised for its smooth, reliable rides and longevity on the road.
Stories of these engines breezing past the 200,000-mile marker are common, showcasing their trustworthy nature. And yeah, it’s not just reliable but popular, too, especially among Mercedes aficionados and everyday drivers alike.
But no engine is without its quirks. The M111 had its own, like head gasket issues leading to those pesky oil leaks and occasional hiccups with the timing chain tensioner.
Some users also pointed fingers at the electronic throttle actuator. Even with these, the M111 maintains its beloved status in the Mercedes-Benz lineup, celebrated for keeping cars reliably on the road year after year.
M104 Engine
Back in the late 1980s, Mercedes-Benz brought this engine to life, blending technology and classic car making in a way that was pretty ahead of its time. This wasn’t just any engine – it was a beast that balanced powerful performance and rock-solid reliability.
Diving into the nitty-gritty, the M104 was a straight-six engine that could be found in sizes from 2.8L to 3.6L. Depending on the model and tweaks, it pumped out anywhere from 190 hp to a hearty 280 hp.
It had a double overhead camshaft and used a sequential fuel injection system, making it a strong performer on the road.
Simply put, this engine wasn’t just tough; it spoke volumes about what Mercedes-Benz engineers were capable of creating.
This mighty engine found a home in several of Mercedes’ beloved models – think the E-Class (like the W124 and W210), C-Class (W202), and even the classy SL-Class (R129).
Stories of these engines breezing past the 300,000-mile mark aren’t hard to find, showcasing that they were built to last.
Drivers loved its smooth, quiet ride and how it delivered power without a fuss, making it an engine that was as reliable as it was fun to drive.
However, the M104 wasn’t perfect. Owners have reported dealing with some pesky issues like the wiring harness wearing down over time and problems with the head gasket, especially as the miles piled up.
There were also some occasional hiccups with the electronic bits in the throttle body.
But even with these flaws, the M104 has kept a warm place in the hearts of Mercedes fans, thanks to its overall sturdy performance and longevity.
OM602 Diesel Engine
When Mercedes-Benz dropped this diesel engine in the 1980s, car folks tilted their hats in respect.
This diesel engine came with a solid 5-cylinder setup and was available in 2.5L and 2.9L sizes. Power? It had it, providing between 90 hp and 130 hp, depending on the exact model and setup.
The engine used a direct injection system, which, at the time, was kind of a big deal, offering better fuel efficiency and a cleaner burn. It was a workhorse that didn’t just show off; it delivered where it counted, on the road, earning it a spot as one of Mercedes’ standout engines.
The OM602 found a home in a variety of Mercedes models, including the well-regarded 300D and 250D. Its smooth, consistent performance and the kind of steadfast reliability that keeps a car running, year in, year out.
Stories of OM602 engines cruising beyond the 500,000-mile mark aren’t just legends; for many, they’re real experiences, creating a legacy of durability and trust among Mercedes owners.
But let’s be real: the OM602 wasn’t without a few headaches. Owners sometimes grumbled about troubles with the fuel injectors, and some faced issues with the timing chain, especially after piling on the miles.
And while it was known for being a generally reliable engine, some folks found it to be a bit noisier or rougher than they’d like.
However, despite these occasional hiccups, many have stuck by the OM602, thanks to its hard-to-beat resilience and performance over the long haul.
M113 V8 Engine
This V8 engine is a sweet ride for folks who dig both power and dependability.
Coming in various sizes, from a hearty 4.3L to a beefy 5.4L, it dishes out anywhere from 275 to 577 horsepower, depending on the model.
What makes the M113 stand out? Well, it boasted a single overhead camshaft design, three valves per cylinder. It used a variable valve timing system, fancy tech that brought a smart balance of power and efficiency to the table.
Plus, it’s got a pretty stellar reputation for being one heck of a reliable engine, and it’s been seen zipping down roads worldwide under the hoods of various models like the E-Class, S-Class, ML, and CL-Class, to name a few.
Now, car folks love this engine, and it ain’t just because it’s reliable. The M113 has got muscle and doesn’t shy away from heavy lifting, which is why it became a go-to for various Mercedes models and even found a spot in some AMG variants. It was a popular choice for those who wanted that extra oomph without tossing reliability out the window.
But, nothing’s perfect, right? The M113 had its fair share of quirks too, like occasional issues with the timing chain guides wearing out or pulley bearing troubles.
But even with a few wrinkles, this engine has remained a favorite in the Mercedes line-up. It’s reliable, it’s strong, and it’s got a track record that makes it stand tall in the crowded world of car engines.
OM606 Engine
The OM606 engine, a piece of Mercedes-Benz’s history, brought a new flavor to the roads from 1993 to 2001.
With an inline-six configuration, this 3.0-liter diesel engine kicked out between 134 to 174 horsepower and 155 to 243 lb-ft of torque, making it not just a reliable buddy on the road but also giving it enough juice to make your rides exciting.
So, why did folks dig the OM606? For starters, it had this robust and sturdy design that was straightforward, easy to maintain, and darn tough.
You could clock in some serious miles on these babies, and they’d keep purring along. Whether you were hauling stuff or cruising down the highway, it had your back with its solid and consistent performance.
It found a cozy home in several Mercedes-Benz models, notably the 1994-1996 E 300 Diesel T Wagon, 1997-1999 E 300 Turbodiesel Wagon, and a few more that offered both space and efficient power on the go.
It wasn’t just the engine’s reliability that won hearts but also its relatively low maintenance and fuel efficiency that made it a hit among long-haul drivers and city cruisers alike.
M116 V8 Engine
This gasoline V8 powerhouse, making its debut in 1969 and strutting its stuff until 1991, certainly made some heads turn.
With displacements of 3.5L, 3.8L, and 4.2L, the M116 offered a respectable 156-228 horsepower and 196-229 lb-ft of torque, ensuring that drivers felt a hearty response with every push of the pedal.
The M116 wasn’t just about power, though. It was a showcase of Mercedes-Benz’s knack for creating engines that could stand the test of time.
With a robust and relatively uncomplicated design, it gained a reputation as a dependable trooper that didn’t blink at high mileage.
It blended smooth rides with a decent punch of power, making it a go-to for folks who wanted the best of both worlds.
This engine found its way into various Mercedes models, including the 1971-1980 C107, 1970-1972 W108, and highly reliable SL420 (R107).
Its reputation for being reliable and relatively easy to work on made it a popular choice among Mercedes enthusiasts and casual drivers alike.
OM603 Engine
The OM603 engine is like that trusty old tool you’ve got in your garage. It ain’t flashy, but dang, it sure gets the job done and never lets you down.
Between 1986 and 1997, this inline-6 diesel engine was the heart of some pretty well-loved Mercedes rides, like the W124 300D and the W140 300SD.
Imagine an engine that doesn’t just drive. It glides, with a 3.0-liter or 3.4-liter displacement, offering a power range of 81-111 hp and torque between 136 and 229 lb-ft. Those numbers mean the OM603 was no slouch on the highways and had the muscle to make those city drives smooth as butter.
Besides cruising with solid power, it was a champ at sipping diesel, giving drivers a neat blend of performance and economy. You’d find it in the smooth-sailing sedans and wagons, like the W124 300D/300D Turbo and the W140 300SD/S350, where it didn’t just work; it excelled, carrying families on vacations and business folks to those must-not-miss meetings.
But no engine is without its quirks. The OM603 wasn’t perfect. Some folks pointed out issues like injector pump leaks and broken injector pipe holders.
It’s a bit of a bummer, sure, but it didn’t push this engine out of the favorites list. Many have cruised well beyond 200,000 miles, with their OM603 still humming steadfastly under the hood.
M103 Engine
Introduced in the mid-80s, the M103 engine from Mercedes-Benz quickly became a legend. This inline-6 gasoline engine was the workhorse behind some of Mercedes’ most iconic cars.
Running from 1984 to 1997, the M103 had two main sizes: a 2.6-liter and a more robust 3.0-liter. Depending on the version, this engine punched out between 158-188 hp and gave a torque of 162-192 lb-ft. Those are pretty impressive numbers for the time being, right?
The M103 was like the heart of several beloved Mercedes models. The W124 300E sedan, the stylish R129 300SL, and the classic W126 260SE all ran with this engine under the hood.
One of the things that made the M103 stand out was its reliability. It wasn’t flashy; it was solid. It was like that trusty friend who’s always there for you, rain or shine. Many of the cars that had this engine could easily go past 200,000 miles, and the engine would still be kicking.
This dependable nature came from its design. Mercedes made the M103 simple but strong. No extra fuss or unnecessary parts – just a good, sturdy engine that did its job.
But, like all things, it wasn’t perfect. Some owners did point out occasional hiccups or issues. Still, when you look at how loved and popular this engine remains, those minor quirks don’t seem like a big deal.
M276 V6 Engine
The M276 V6 engine is a bit of a star in the Mercedes-Benz world. Kicking off its journey in the early 2010s, this engine quickly found its way into the hearts of car lovers.
This V6 engine, boasting a displacement that ranges typically around 3.0 liters, could sing to the tune of 248 to 329 hp and flex with a torque of 251-354 lb-ft.
This gasoline engine didn’t just stay put in one type of car. It moved around, showing off its skills in various Mercedes models, such as the beloved E350, the sleek SL350, and even the bigger guys like the ML350 and GL350.
The M276 was like that reliable buddy that knew how to party – powerful, but also knew when to keep it cool and steady, giving drivers a balanced and dependable ride.
It was versatile, fitting comfortably in both the sedans and the SUVs, offering a kind of one-size-fits-all solution to different kinds of Mercedes vehicles.
However, no engine is without its quirks. Some folks using the M276 have pointed out that it could be a tad thirsty on the oil, and others have noted that it sometimes had issues with its timing chain.
So, while it wasn’t perfect, the M276 V6 was still a champ in reliability and performance in the grand scheme of things.
