Oil leaks are among the most frustrating issues car owners face—messy, expensive, and often a sign of deeper problems. While regular maintenance is key, some engines are simply built better, with tighter tolerances, superior materials, and better gaskets and seals.
Whether you’re buying a used car or planning your next long-term daily driver, here are 10 engines with a reputation for staying dry and reliable over the years.
When it comes to vehicle ownership, few things are more frustrating—or potentially costly—than an oil leak. Whether it’s a small drip on the driveway or a more serious issue under the hood, oil leaks can lead to degraded performance, engine damage, and expensive repairs. For car owners who value reliability and longevity, engine integrity is a top priority.
That’s why choosing a vehicle with an engine known for its durability and oil-tight construction can make all the difference over the long haul.
In the sea of internal combustion engines flooding the auto market over the decades, some have earned a sterling reputation for staying sealed and solid, mile after mile.
These engines don’t just run—they keep running, often outlasting the cars they’re in. While most engines will eventually show their age through minor seepage or gasket fatigue, a select few stand out for their exceptional engineering, precision machining, and superior materials that resist oil leaks even after years of use.
In this article, we’ll highlight 10 legendary engines that are widely regarded for their ability to resist oil leaks and hold together longer than most. Whether you’re a seasoned mechanic, an enthusiast searching for your next project car, or simply a driver who wants a low-maintenance ride, this list will guide you toward the engines that just don’t quit—or drip.
From Japanese efficiency to German engineering, these powerplants have earned their reputations through years of proven performance, clean garage floors, and happy owners.
Let’s dive into the engines that are built to last—and keep their oil where it belongs.
1. Toyota 2.5L I4 (A25A-FKS) – Camry, RAV4, Highlander
Toyota’s 2.5L inline-four is the latest in the brand’s Dynamic Force engine family. Known for its thermal efficiency and rock-solid reliability, this engine is remarkably well-sealed. It’s used across a wide range of models and has shown virtually no systemic oil leak problems, even past 100,000 miles.
Toyota launched the A25A-FKS, also known as the 2.5 D-4S engine, in 2016 as the inaugural member of its new “Dynamic Force Engines” family. This 2.5-liter inline four-cylinder gasoline engine integrates Toyota’s latest internal combustion technologies, many of which had previously been implemented separately in other engines over recent years.
The A25A features a newly developed open-deck aluminum alloy cylinder block with cylinder sleeves cast directly into the block material. The crankshaft’s longitudinal axis is offset by 10 mm relative to the cylinder axes.
It includes seven traditional counterweights and an additional one fitted with a toothed gear. This gear drives a balance shaft unit mounted at the bottom of the engine block. The engine incorporates high-strength connecting rods and lightweight aluminum T-shaped pistons, which are coated with a special resin.
The upper compression rings and oil control rings are treated with a Diamond-Like Carbon (DLC) coating. Piston cooling is achieved through engine oil sprayed by two dedicated oil jets per piston. Enhancements to the oil system include the adoption of a second-generation variable-pressure oil pump, which is electronically controlled by the ECM.
The engine is equipped with an aluminum 16-valve cylinder head, featuring two chain-driven camshafts housed in a separate top-mounted casing. The angle between the intake and exhaust valves is set at 41 degrees.
The intake port uses a laser-cladded valve seat, whereas the exhaust port is fitted with a conventional pressed-in valve seat. Valves are actuated by the camshafts through roller rocker arms. Hydraulic tappets are used to maintain continuous zero valve clearance. A low-friction single-row timing chain with an 8.0 mm pitch drives both camshafts.
The A25A-FKS is equipped with a Dual Variable Valve Timing (DVVT) system: the intake camshaft utilizes an electric actuator (VVT-iE), while the exhaust camshaft employs a traditional hydraulic VVT actuator. Additionally, the exhaust camshaft includes an extra lobe for driving the high-pressure fuel pump. The cylinder head cover is manufactured from polymer composite material.
This engine uses a combined fuel injection system—direct injection into the combustion chambers and multipoint injection into the intake ports—referred to by Toyota as D-4S. Each high-pressure fuel injector for direct injection features six holes and is active during mid to high engine loads.
The low-pressure port injectors have ten holes and operate primarily at low engine speeds, as well as in conjunction with direct injection during mid-range operation. Fuel pressure across the system ranges from 2.4 to 20 MPa.
Air intake is handled by a fixed-geometry plastic intake manifold and an electronically controlled throttle body (ETCS-i). Because the intake manifold design does not restrict airflow, a vacuum pump—driven by the exhaust camshaft—was added to ensure adequate vacuum is available for the brake booster.
On the exhaust side, the engine is fitted with a stainless steel manifold (header) that includes an integrated catalytic converter and an EGR (Exhaust Gas Recirculation) pipe.
Also Read: Top 12 Cars That Run Like New Even After 15 Years With Minimal Maintenance
2. Honda 1.5L Turbo I4 (L15B7) – Civic, CR-V, Accord
While early models raised concerns about oil dilution, Honda has since addressed the issue. The L15B7 is now known not just for its fuel economy and smooth power delivery but also for its clean oil performance. With routine maintenance, these engines rarely suffer from oil leaks.
The L15B7 is a 1.5-liter inline four-cylinder turbocharged gasoline direct-injection engine that made its debut in the 2016 Honda Civic. This engine was developed as part of Honda’s downsizing strategy, which focuses on smaller displacement engines paired with turbocharging to compensate for any power deficit.
As a result, the 1.5L turbocharged unit delivers strong fuel efficiency while also producing power and torque levels that surpass those of a naturally aspirated 2.4-liter engine. Honda has since expanded the application of the 1.5T engine to include larger, heavier vehicles like the Honda CR-V and Honda Accord.
To understand what makes the Honda 1.5L turbo engine both powerful and efficient, it’s important to examine its engineering details. The engine is built around an aluminum open-deck cylinder block paired with an aluminum cylinder head. Within the block, lightweight steel connecting rods—heat-forged for enhanced strength—are used to handle high operating loads.
The pistons have a cavity-shaped design and an optimized skirt to reduce friction and vibration, improving overall engine efficiency.
Additionally, Honda employs a plateau honing technique on the cylinder walls, which is a fine grinding process that further minimizes friction between the piston and cylinder. Piston cooling is managed through oil spray jets that target the underside of each piston.
The cylinder head design incorporates four valves per cylinder and uses a dual overhead camshaft (DOHC) setup, driven by a timing chain. Both the intake and exhaust camshafts are equipped with VTC (Variable Timing Control) actuators. Each direct fuel injector—featuring multiple spray holes—is positioned between the intake valves, while the spark plug is centrally located at the top of each combustion chamber.
A key feature of the cylinder head is its high tumble intake ports, with a tumble ratio of 1.9, which enhance airflow into the combustion chamber and promote more efficient combustion. Another important element of the 1.5T engine is the water-cooled exhaust manifold, which is integrated into the cylinder head.
The exhaust port passages are cast directly into the head, allowing exhaust gases to be cooled by up to 100 degrees Celsius. This cooling extends the life of turbocharger components and contributes to quicker engine warm-up.
The L15B7 is equipped with an MHI-TD03 mono (single)-scroll turbocharger, which features small-diameter turbines and an electronically controlled wastegate. This compact turbo design helps reduce turbo lag and ensures quick response during acceleration.
In the standard U.S. Civic configuration, the turbo delivers 16.5 psi of boost pressure and works with a 10.6:1 compression ratio. To manage the temperature of intake air—heated during compression by the turbocharger—the engine utilizes a conventional air-to-air intercooler. After being cooled, the intake air flows into a plastic intake manifold.
Engine speed and throttle response are regulated by an electronic drive-by-wire system, eliminating any mechanical linkage between the accelerator pedal and the throttle valve. This system allows for more precise throttle control and improved integration with the engine’s electronic control systems.
3. Mazda 2.5L Skyactiv-G I4 – Mazda3, Mazda6, CX-5
Mazda’s naturally aspirated Skyactiv engines are engineering standouts. The 2.5L Skyactiv-G has very few reported issues related to oil leaks. Its high-compression design and precision machining contribute to its excellent sealing and low oil consumption over time.
The 2.5 SkyActiv-G engine (designated PY-VPR and PY-VPS) is a 2.5-liter gasoline engine that was first introduced in the Mazda KE CX-5 and the GJ Mazda6 in 2012. This engine builds upon the same technologies and engineering principles that were already established with the 2.0 SkyActiv-G. However, the 2.5-liter version is not simply a larger displacement variant—it incorporates several distinct features of its own.
To begin with, the SkyActiv 2.5 was developed as a replacement for the L5-VE engine. Like its predecessor, it features an aluminum alloy cylinder block, utilizing 4340 steel-molybdenum alloy for the cylinder bores.
A key addition in this larger four-cylinder SkyActiv-G engine is the inclusion of a balancer unit. This system consists of two balancing shafts, driven by a crankshaft gear, that rotate at twice the speed of the crankshaft to reduce engine vibration.
The block has been engineered with a larger bore and stroke to achieve a total displacement of 2,488 cc. All internal engine components have been optimized to be lighter and stronger. These include a forged steel crankshaft, forged connecting rods, and aluminum pistons. Friction in the lower end of the engine has been reduced by 30 percent.
The cylinder head design closely resembles that of the 2.0-liter SkyActiv-G. It is made from an aluminum-silicon alloy and features dual overhead camshafts, four valves per cylinder, and rocker arms equipped with needle roller followers to enhance efficiency and durability.
The 2.5 SkyActiv-G is equipped with Mazda’s variable valve timing system known as ‘Dual Sequential Valve Timing’ (Dual S-VT). The fuel system was also significantly improved.
It features a direct fuel injection setup that delivers fuel directly into the combustion chambers. This system includes a highly efficient high-pressure fuel pump and six-hole injector nozzles to promote better atomization and a more precise air-fuel mixture.
This engine carries the ‘SkyActiv-G’ label due to its unusually high compression ratio for a gasoline engine—14.0:1 under standard specifications. However, for markets such as the United States, Canada, and Australia, the compression ratio is slightly reduced to 13.0:1 to accommodate local fuel standards.
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4. Ford 2.5L Duratec I4 – Fusion, Escape, Transit Connect
While some Ford engines have spotty reputations, the 2.5L Duratec inline-four is the exception. This older but proven design is simple, robust, and leak-resistant. It lacks the complexity of turbochargers and direct injection, which also helps it stay sealed over the years.
The Duratec 25, also referred to as the Mazda L engine, is a 2.5-liter naturally aspirated four-cylinder engine developed by Ford Motor Company. It has been employed in powering midsize cars, cargo vans, and sport utility vehicles—commonly known as SUVs.
The engine features a dual overhead camshaft (DOHC) layout in an inline configuration and has been part of the Ford Duratec engine lineup since 2008, although it made its debut in the North American market in 2009. This engine emerged from a collaborative development effort with Mazda—classified under the MZR engine family—but was created during a period of Ford ownership.
This relationship accounts for its use across a wide range of vehicle applications between the two brands. The resulting variations led to numerous technologies being integrated into the engine over time, including the Atkinson cycle, hybrid system components, and adaptive knock control, all aimed at enhancing fuel efficiency.
5. GM 3.6L V6 (LGX) – Chevrolet Camaro, Cadillac CT6, GMC Acadia
General Motors’ LGX 3.6L V6 is one of the company’s most leak-resistant V6s to date. It uses high-quality gaskets and improved crankcase ventilation, avoiding the oil seepage issues that plagued earlier GM V6s. Owners routinely report high mileage without drips.
Doing your own research is always a smart move before spending a significant amount of money on a vehicle—especially when it comes to a GM product that uses this particular engine. We emphasize this because the GM 3.6L engine has been known to suffer from a range of issues. This is precisely why proper research is essential, and it’s exactly where we step in to help you make an informed decision.
We’ll start by covering the technical specifications and vehicle applications of the GM 3.6L engine. After that, we’ll dive into the common problems and its overall reliability. So, without further delay, let’s get into the details.
The GM 3.6L engine was first introduced in 2004 and is part of the GM High Feature engine family. These are V6 engines ranging from 2.8 to 3.6 liters in displacement, developed to power various GM vehicles across different brands, including Holden, Cadillac, Chevrolet, and others.
These engines were especially common in larger vehicles such as full-size sedans and SUVs. Among the lineup, the 3.6L is the largest displacement variant. It is configured as a 60-degree V6 engine and features a displacement of 3.6 liters.
Although the engine design is now considered outdated, it was fairly innovative at the time of its release. One of the standout improvements came with the second generation, which introduced direct fuel injection—a notable step forward in terms of efficiency and performance.
Another unique aspect of this engine is its flexibility in fuel types; it was capable of running on autogas and E85 ethanol blends. The engine is chain-driven, and unfortunately, this design is the source of several well-known issues. Timing chain reliability has been one of the major weak points, often resulting in long-term durability concerns.
6. Subaru 2.5L Flat-4 (FB25) – Outback, Forester, Legacy
Older Subarus were notorious for head gasket leaks, but the FB25 engine turned the tide. Subaru refined the sealing surfaces and gasket material in the FB series, dramatically reducing oil and coolant leaks. It’s a big reason why newer Subarus have become more attractive to reliability-minded buyers.
The FB25 (also known as FB25B) is derived from the FB20 aluminum cylinder block, retaining its cast iron sleeves. In order to increase displacement, Subaru expanded the bore to 94 mm while keeping the stroke unchanged. As a result, the cylinder wall thickness is relatively slim at only 3.5 millimeters. Naturally, the FB25 received newly designed pistons, which lowered the compression ratio to 10:1.
Each side of the engine block features an aluminum DOHC 8-valve cylinder head—four valves per cylinder—with roller rocker arms. The FB-series heads are constructed in two parts: the main cylinder head and a separate camshaft carrier. This design approach reduces both the amount of metal used and the overall weight of the engine.
The FB25 also benefits from maintenance-free timing chains, which drive both camshafts. These camshafts come equipped with Subaru’s dual Active Valve Control System (AVCS), offering variable valve timing for improved performance. Another notable change is the relocation of the fuel injectors to the cylinder heads.
This adjustment makes the injection system more complex, but it enhances its overall efficiency. The exhaust system was also improved. The engine uses newly designed exhaust manifolds with optimized tubing diameters, which contribute to faster catalytic converter warm-up and improved power output.
In terms of performance, the FB25 delivers better low-end response compared to its predecessor, the EJ25. Although it maintains the same peak horsepower, it offers increased torque at lower RPMs, making it more responsive in daily driving scenarios. This improvement also leads to better fuel efficiency. Because of these refinements, Subaru’s new 2.5-liter engine is a more practical option for drivers seeking to reduce fuel costs without sacrificing performance.
7. Hyundai/Kia 2.0L MPI I4 (Nu Engine) – Elantra, Forte, Soul
This multi-point injection (MPI) version of Hyundai’s Nu engine is impressively reliable. Unlike its GDI (direct injection) counterparts, the MPI setup runs cooler and cleaner, and oil leaks are rare even after years of daily commuting. Just stick to regular oil changes, and this engine will reward you.
The 2.0 MPi engine, a cornerstone in the Hyundai and KIA lineup, is a naturally aspirated four-cylinder unit that has earned a solid reputation in the automotive market since its debut. This engine is well-regarded for its balanced performance, dependable efficiency, and solid reliability, making it a favored option across a wide range of vehicle categories.
Engineered with the goal of delivering a smooth and consistent driving experience, the 2.0 MPi is built to appeal to both everyday drivers and those looking for a bit of added engagement behind the wheel.
Beneath the surface, the 2.0 MPi is designed to strike an effective balance between power output and fuel economy. Producing approximately 147 horsepower and 132 lb-ft of torque, it may not deliver overwhelming performance, but it offers more than enough capability for typical driving conditions.
The engine’s design highlights include a lightweight construction and optimized combustion process, both of which contribute to its well-rounded performance in city traffic and on open highways alike. Central to its efficiency is the MPi (Multi-Point Injection) system, which ensures precise fuel atomization across all cylinders.
This technology improves combustion quality, resulting in enhanced fuel efficiency and lower emissions. Compared to some turbocharged alternatives, the 2.0 MPi engine stands out as a more environmentally conscious choice without sacrificing dependable everyday performance.
8. BMW 3.0L I6 (B58) – 3 Series, Supra, Z4
BMW isn’t usually synonymous with leak-free engines, but the B58 straight-six breaks the mold. Introduced as part of BMW’s modular engine family, the B58 has earned a reputation for durability and excellent sealing. It’s smoother, stronger, and far more reliable than the N54 and N55 engines that came before it.
BMW’s B58 engine is a 3.0-liter inline-six turbocharged gasoline powerplant with direct injection, in production from 2016 to the present. Like the N55 before it, the B58 employs a single twin-scroll turbocharger.
However, it distinguishes itself from its predecessor by utilizing an air-to-water intercooler, which significantly enhances cooling efficiency. Additionally, it features a shortened intake tract, contributing to quicker throttle response and improved engine dynamics.
Since its introduction in 2016, the B58 has powered a wide array of BMW models, ranging from compact performance cars like the F20 M140i to full-size luxury vehicles such as the G07 X7. This engine has built a reputation not just for exceptional reliability, but also for its high tuning potential.
The B58 has earned four Ward’s 10 Best Engines awards, a testament to its engineering excellence. Thanks to its robust closed-deck block, forged crankshaft, and impressive performance capabilities, it outperforms its predecessor and stands out among non-M BMW engines. In terms of both reliability and performance, the B58 scores nearly perfect marks.
This page serves as the ultimate hub for everything related to the BMW B58. It includes a detailed overview and technical breakdown of the engine, along with information on common issues, performance upgrades, tuning potential, frequently asked questions, and a wide range of additional resources. Whether you’re already driving a B58-powered BMW or considering purchasing one, this is the most comprehensive source of B58 information available online.
9. Mercedes-Benz 2.0L Turbo I4 (M274) – C-Class, GLC, E-Class
Mercedes engines have traditionally struggled with leaks, but the M274 turbocharged four-cylinder is a notable exception. With updated timing cover designs and higher-quality seals, the M274 resists leaks even well beyond 100,000 miles, making it a standout in modern German engineering.
The Mercedes-Benz M274 and M270 engine series consist of 1.6-liter and 2.0-liter four-cylinder gasoline engines developed for both front- and rear-wheel-drive vehicles. Production began in 2011 at the Mercedes-Benz plant located in Stuttgart Untertürkheim, with additional manufacturing taking place at MDC Power GmbH in Kolleda.
These engines were introduced as replacements for the older M266 and M271 EVO families. The M270 versions (designated M270.910 and M270.920) are designed for front-wheel-drive vehicles with a transverse engine layout and are commonly found in models such as the A-Class, B-Class, CLA-Class, GLA-Class, GLC-Class, and others.
On the other hand, the M274 variants (M274.910 and M274.920) are tailored for rear-wheel-drive vehicles, where the engine is mounted longitudinally—these include models like the C-Class and E-Class.
Structurally, the M274/M270 engines are built around a diecast aluminum cylinder block (crankcase) that utilizes an open-deck design. The engine employs cast iron cylinder liners, and both the 1.6-liter and 2.0-liter versions share a standardized bore size of 83 mm (3.27 in). The primary distinction between the two lies in the stroke length, with an 18.3 mm (0.72 in) difference that accounts for the 0.4-liter increase in displacement.
A hollow-cast crankshaft featuring four counterweights is used to minimize weight. In the 2.0-liter version, a compact Lanchester module is integrated to counteract second-order inertial forces, effectively lowering noise, vibration, and harshness (NVH) levels. This module is fastened to the crankshaft bearing block from the underside.
The bottom end of the engine includes a diecast aluminum oil pan, which contributes additional structural rigidity. Inside the oil pan is the oil pump, which is driven by the crankshaft through a toothed chain. This is a regulated oil pump system, with oil pressure being electronically managed by the ME-SFI (ME) control unit.
10. Lexus 3.5L V6 (2GR-FKS) – RX350, ES350, Toyota Highlander
The 2GR-FKS is part of Toyota’s bulletproof GR engine family and powers many Lexus and Toyota vehicles. Known for its smooth power delivery and quiet operation, this engine is also exceptionally leak-resistant. Owners frequently report passing 200,000 miles with no oil issues beyond standard changes.
Even the best engines can develop leaks if they’re abused or poorly maintained. But when properly serviced, the engines listed above are among the most durable and leak-resistant in the industry.
Whether you’re in the market for a reliable daily driver or planning to hold onto your car for the long haul, choosing a powerplant known for dry reliability could save you thousands in repairs—and a few unsightly stains on your driveway.
Toyota’s 3.5-liter V6 gasoline engine, designed for transverse mounting, was first introduced in 2004. This engine, known as the 2GR-FE, was developed to replace both the earlier 1MZ-FE V6 and the legendary inline-six 2JZ engines.
The 2GR-FE quickly became a widely adopted option across a range of mass-market Toyota vehicles such as the Toyota Camry, RAV4, and Highlander.
Its usage extends well beyond the Toyota lineup, being prominently featured in numerous Lexus models carrying the “350” badge—examples include the Lexus IS 350, GS 350, RX 350, among others. Additionally, it powered performance-oriented cars like the Lotus Evora S and Exige S.
Structurally, the 2GR-FE shares design elements with the 1GR-FE, including an open-deck cast aluminum alloy cylinder block that incorporates spiny-type cast iron cylinder liners.
These liners are cast directly into the aluminum block, and the engine’s 60-degree V-angle between the cylinder banks promotes a compact design. The engine is built with a forged steel crankshaft equipped with five counterweights, along with forged connecting rods for added strength and durability.
The pistons are made from aluminum alloy and feature resin-coated skirts to help reduce friction during operation. Additionally, the engine block includes oil jets specifically designed to spray oil onto the pistons, helping to lower piston temperatures and enhance overall thermal efficiency.
Each cylinder head in the 2GR engine is composed of three distinct components: the main cylinder head, the camshaft housing, and the valve cover. All three parts are manufactured from aluminum alloy.
Between the cylinder banks and the heads, steel-laminate type head gaskets are used to ensure proper sealing. The engine employs dual overhead camshafts for both intake and exhaust on each cylinder bank, all of which are driven by chains. The primary timing chain is responsible for driving only the intake camshafts, while the exhaust camshafts are powered through secondary chains linked to the intake cams.
The valve timing system utilizes Toyota’s Dual VVT-i technology, which allows for continuous adjustment of both intake and exhaust camshaft timing. The valves are actuated using roller rocker arms, and valve clearance is automatically maintained through hydraulic lash adjusters (tappets), eliminating the need for manual adjustment.
