Is the 4-cylinder 4Runner reliable?

Yes, overall a 4-cylinder 4Runner can be reliable when properly maintained, but the 4-cylinder option is uncommon in newer US-market models and may not be as widely supported as the V6. Reliability largely depends on maintenance history, model year, and how the vehicle has been driven.

The Toyota 4Runner is built as a rugged, body-on-frame SUV with a long reputation for longevity. Historically, Toyota offered a four-cylinder variant in some generations and markets, but today the U.S. lineup is dominated by V6 power. This article explains what buyers should know about reliability when considering a 4-cylinder 4Runner, including engine design, maintenance considerations, and how reliability can vary by generation.

Engine basics and what to expect

The 4-cylinder version of the 4Runner, where it exists in older generations or markets outside North America, typically used a compact inline-four with a timing chain and a focus on durability over high power. In most North American model years, the 4Runner’s powertrain emphasis has been on a V6 for torque, towing, and on-road capability. If you are shopping a used example, verify the exact engine code and service history, since parts availability and known issues can differ by engine family.

Reliability landscape: strengths and caveats

Below are the key reliability factors commonly cited by owners and reviewers for 4-cylinder 4Runners. The list helps set expectations for what tends to hold up well and where to watch for potential issues.

• Proven Toyota engineering: Inline-four engines from Toyota’s lineage used in older 4Runners tend to be robust with long potential lifespans when oil changes and routine maintenance are kept on schedule.


• Fewer moving parts than modern turbo engines: A naturally aspirated four-cylinder usually has fewer components that can fail than a modern turbo or large-displacement setup, which can translate to lower maintenance risk in some scenarios.


• Simple design aids longevity: A simpler cylinder head and valvetrain arrangement can be less prone to certain failures over time, contributing to strong reliability in aging units.


• Strong aftermarket support and used-market familiarity: Many shops are comfortable with older Toyota four-cylinders, which can reduce maintenance costs and increase repair accessibility.


• Great longevity with diligent care: With regular oil changes, cooling system upkeep, and timely component replacements, these engines can reach high mileages well over 200,000 miles.

For context, reliability varies by generation and region. While the four-cylinder variant is not the default in the latest U.S. market 4Runners, the underlying Toyota approach to durability—maintenance-first ownership, clear service intervals, and accessible parts—generally supports strong long-term reliability when applied to any 4-cylinder powerplant used in the 4Runner family.

Generation-by-generation considerations

Different generations of the 4Runner used different four-cylinder designs, each with its own reliability profile. Here are high-level notes to guide a potential buyer or owner.

• Early and transitional generations (where a 4-cylinder was offered): These engines are typically simple, proven designs. Their reliability hinges on standard maintenance like oil changes, coolant service, and timely replacement of belts or hoses as applicable to the era.


• Mid- to late-generation shifts: As Toyota refined the platform, the emphasis shifted toward the V6 in U.S. models. Four-cylinder variants may be more common in other markets or older model years, but parts availability and service documentation can vary by region. Always check the exact engine code and recall history when buying used.


• Current U.S. market reality: Modern 4Runners in the United States are powered primarily by V6 engines, with the 4-cylinder option not being offered on the current generation. If reliability for a 4-cylinder is the goal, consider historical models or non-U.S. markets and verify maintenance records and engine internals before purchase.

Before considering a purchase, verify the engine code, service history, and any region-specific notes. A well-documented maintenance trail can dramatically influence long-term reliability, regardless of engine size.

Maintenance practices to maximize reliability

Maintenance discipline is the best predictor of reliability for any used vehicle, and the 4-cylinder 4Runner is no exception. The following practices help keep these engines running smoothly over the long term.

• Stick to recommended oil-change intervals with the correct viscosity and quality oil for the engine. Regular oil changes are crucial for longevity in older Toyota four-cylinders.


• Keep the cooling system in good shape: coolant condition, radiator, hoses, thermostat, and the water pump should be inspected and replaced as needed to prevent overheating, which can accelerate wear on the engine and head gaskets.


• Monitor and replace ignition components as needed: spark plugs and ignition coils or packs should be serviced according to the vehicle’s maintenance schedule to prevent misfires and rough running.


• Check for signs of oil consumption or leaks and address them early. Some longer-lived four-cylinders can develop leaks or gradual consumption with age; addressing these symptoms early helps prevent bigger issues.


• Inspect the timing mechanism: if the engine uses a timing chain, ensure the chain and related guides/tensioners are in good condition to avoid timing-related failures.


• Maintain the cooling fans, sensors, and electrical connections: electrical gremlins and cooling fan failures are common wear points in aging engines, and addressing them promptly reduces the risk of overheating and related damage.

Implementation of these practices, along with choosing a well-documented example (with a clear maintenance log and fewer high-stress duty cycles), will maximize reliability for a 4-cylinder 4Runner model you’re considering or already own.

Conclusion and key takeaways

In short, a 4-cylinder 4Runner can be a durable, long-lasting vehicle if you prioritize maintenance and align expectations with its capabilities. The four-cylinder option is not the default in many newer models, and power, towing capacity, and parts availability can differ from the V6 variant. For buyers, the most reliable path is to inspect the specific engine code, review the maintenance history, and ensure routine service has been followed. When these conditions are met, a 4-cylinder 4Runner can deliver the same Toyota reliability the brand is known for, with the caveat of reduced torque and potentially lower resale familiarity compared with the V6 models.

Summary

The 4-cylinder 4Runner is generally reliable when properly maintained, benefiting from Toyota’s durable engineering and easier maintenance compared with more complex powertrains. Reliability is highly dependent on generation, market, and most critically, the vehicle’s maintenance history. If you are shopping used, verify the exact engine code, review service records, and be mindful that modern U.S.-market 4Runners emphasize a V6 option, while 4-cylinder variants may require extra diligence in sourcing parts and confirming long-term upkeep plans.

Which year 4Runner to avoid?

You should avoid the 2003–2005 4Runners due to serious frame rust, head gasket issues, and dashboard cracking. Other years to consider avoiding are the 2001–2002 models for safety concerns and rust, and the 2015 model for infotainment and brake problems. 
2003–2005 (Fourth Generation) 

• Severe frame rust: This is a major issue, with many owners reporting the frame is irreparable. 
• Head gasket failure: V6 models, in particular, are prone to head gasket issues, which can be a costly repair. 
• Dashboard cracking: Owners have reported the dashboard cracking. 
• Other issues: Includes reports of faulty anti-lock brake systems (ABS), air injection pump failures, and check engine light problems. 

2001–2002 (Third Generation) 

• Safety rating: These models have low crash test scores, particularly in rear impacts. 
• Body rust: Prone to rust, making them unreliable for some families. 
• Off-road limitations: Manual transmission and locking rear differentials were eliminated during these years. 

2015 (Fifth Generation) 

• Infotainment issues: This model is known for an unreliable infotainment system that freezes, restarts, and has Bluetooth connection problems. 
• Brake problems: Owners have reported warped brake rotors. 
• Steering complaints: There are more NHTSA complaints about steering problems compared to other fifth-gen models. 
• Airbag defect: The 2015 is the only fifth-generation model with reported airbag non-deployment issues, which is a significant safety concern. 

What is Toyota's most reliable 4-cylinder engine?

The most reliable Toyota 4-cylinder engines include the older 22RE and 4A-GE, and modern options like the A25A-FKS and the hybrid system's 2.5L engine. Older engines like the 22RE are praised for their durability and simplicity, while newer engines like the A25A-FKS benefit from modern engineering and have shown excellent long-term reliability. Toyota's hybrid 4-cylinders are also considered exceptionally reliable due to their robust design and accompanying ECVT transmission.
 
You can watch this video to learn about some of Toyota's most reliable engines: 56sSUV ZoneYouTube · Aug 13, 2025
Older engines

• 22RE (2.4L): A legendary engine known for its "over-engineered" and simple design, making it incredibly durable. It was the backbone of Toyota's truck and SUV lineup for many years. 
• 4A-GE (1.6L): This high-revving, naturally aspirated engine was known for its robust design and high-performance capabilities, appearing in models like the MR2 and Corolla. 

Modern engines

• A25A-FKS (2.5L): This naturally aspirated engine is part of the Dynamic Force engine family and is noted for its simplicity and low maintenance costs. It has demonstrated excellent reliability in modern vehicles. 
• T24A-FTS (2.4L Turbo): An evolution of the A25A, this turbocharged engine is also designed for efficiency and has shown no widespread issues, making it a reliable choice despite having slightly higher maintenance costs due to its turbo components. 
• Hybrid 2.5L engine: The hybrid system found in many modern Toyota and Lexus models combines a straightforward 2.5L 4-cylinder with electric motors. This system is considered one of the most reliable drivetrains available, often lasting well over 250,000 miles. 

This video explains the reliability of Toyota's hybrid engine system: 1mCar Help CornerYouTube · Jun 15, 2025

How reliable is Toyota's 2.4 turbo engine?

The reliability of the Toyota 2.4L turbo engine is still developing, but early signs are positive, with no widespread issues reported, though some owners have experienced isolated problems. The engine is new, so long-term durability is not fully proven, but it uses advanced technology and has been in use in Lexus vehicles since 2021, indicating a degree of proven design. While long-term dependability is unknown, adherence to the maintenance schedule is key, and early quality ratings are high. 
This video discusses the reliability of the Toyota 2.4L turbo engine: 59sMotormouthYouTube · Nov 20, 2023
Potential concerns and considerations

• Long-term durability: It is still too early to definitively compare the long-term reliability of the 2.4L turbo engine to Toyota's older, naturally aspirated engines. 
• Complexity: The engine features many modern components, such as a direct injection system, a turbocharger, and a balancing shaft with polymer gears, which could increase potential failure points. 
• Maintenance: Following the manufacturer's maintenance schedule is crucial for the longevity of this new engine. 
• Isolated incidents: Some owners have reported isolated issues, such as transmission problems or turbo failure, but these appear to be specific instances and not indicative of a systemic problem. 

This video discusses the design and potential failure points of the 2.4L turbo engine: 58sGetty's GarageYouTube · Aug 17, 2025
Positive indicators

• Predecessor in Lexus: The engine has been used in Lexus vehicles since 2021 with no major reliability concerns reported. 
• J.D. Power ratings: Recent models with the T24A-FTS engine have received good scores in J.D. Power's Initial Quality Study, suggesting good early reliability. 
• Warranty: Any potential issues with components like the turbo sensor are typically covered under Toyota's warranty for newer vehicles. 
• Maintenance: Sticking to the maintenance schedule can help ensure durability, with many owners reporting trouble-free driving up to 100,000 miles. 

How long does a Toyota 4-cylinder last?

The Toyota name guarantees that any car powered by one of their engines will last for a very long time, regardless of the model you choose. They usually endure well over 200,000 or even 250,000 miles, while the precise mileage for a vehicle varies depending on the type and the care you give it.