Ringland Failure in 2019 Subaru STI: What You Need to Know

If you’re a performance car enthusiast, the Subaru WRX STI should be on your radar. This rally-inspired car has been a fan favorite for years, thanks to its impressive handling, all-wheel drive, and powerful turbocharged engine. However, there’s one issue that many Subaru owners have faced: ringland failure.

In this article, we’ll dive into the issue of ringland failure in Subaru engines and explore whether or not the 2019 Subaru STI will have less of this type of failure. We’ll also provide practical advice for those who own or plan to own a Subaru WRX STI.

Key Takeaways

  • Ringland failure is a common issue in high-performance Subaru engines, in which a portion of the piston’s ringland breaks or cracks due to excessive heat and pressure.
  • Subaru has made several changes to the 2019 STI engine to address ringland failure, including new pistons, a redesigned intake manifold, and revised tuning.
  • While these changes may reduce the likelihood of ringland failure, it’s still important for owners to take precautions to prevent it, such as using high-quality oil and coolant, avoiding aggressive driving and engine modifications, and keeping up with regular maintenance.

What is Ringland Failure?

Before we dive into the specifics of ringland failure in Subaru engines, let’s first understand what a "ringland" is. In a piston engine, the piston moves up and down in the cylinder, compressing fuel and air before combustion. The piston is equipped with one or more rings, which are designed to seal the combustion chamber and prevent oil from entering the cylinder. The piston’s ringland is the portion of the piston between the rings, where the material is thinnest.

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Ringland failure occurs when a portion of the piston’s ringland breaks or cracks. This can be caused by a number of factors, but the most common is excessive heat and pressure in the engine. When the engine is under load, such as during hard acceleration or track driving, the temperature and pressure inside the combustion chamber can skyrocket, causing the piston to expand and potentially crack the ringland. This can lead to a loss of compression and power, as well as engine damage if not caught early.

Ringland Failure in Subaru Engines

Ringland failure is a well-known issue in high-performance Subaru engines, particularly those in the WRX and STI models. Many owners have reported experiencing this problem, often after modifying their cars for more power or driving aggressively.

There are several reasons why Subaru engines are more prone to ringland failure than other performance engines. One is the design of the boxer engine, which places the pistons horizontally opposed and parallel to the ground. This design can make it more difficult for heat to dissipate away from the pistons, leading to higher temperatures and increased likelihood of failure.

Additionally, Subaru engines tend to have thinner ringlands than other engines, which can make them more vulnerable to cracking under extreme conditions. Finally, many Subaru owners tend to modify their cars for more power, which can put additional stress on the engine and exacerbate the issue of ringland failure.

What is Subaru Doing to Address Ringland Failure in the 2019 STI?

Given the prevalence of ringland failure in Subaru engines, you might be wondering what Subaru is doing to address this issue in the 2019 STI. Here are some of the changes that have been made to the engine:

  • New pistons: Subaru has redesigned the pistons in the 2019 STI engine to be stronger and more durable. These new pistons feature a reinforced skirt and thicker ringland area to help prevent cracking under high loads.

  • Redesigned intake manifold: The intake manifold on the 2019 STI has been redesigned to improve air flow and reduce heat soak. This should help keep temperatures down and reduce the likelihood of ringland failure.

  • Revised tuning: Subaru has also made changes to the engine’s tuning to improve overall reliability and reduce the likelihood of knock, which can be a contributor to ringland failure.

  • Other changes: In addition to these changes, Subaru has also made several other improvements to the 2019 STI, such as a revised suspension, stronger transmission gears, and a larger intercooler.

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While these changes are certainly promising, it’s important to note that they may not completely eliminate the risk of ringland failure in the 2019 STI. High-performance engines are always going to be more prone to failure under extreme conditions, and it’s ultimately up to the driver to take precautions to prevent it.

How to Prevent Ringland Failure in Your Subaru

Whether you own a 2019 STI or an older Subaru model, there are several steps you can take to minimize the risk of ringland failure. Here are some tips:

  • Use high-quality oil and coolant: High-performance engines require high-quality fluids to perform at their best. Make sure you’re using a high-quality synthetic oil and coolant that are designed for your car’s specific needs.

  • Avoid aggressive driving and engine modifications: While it can be tempting to push your car to its limits, doing so can put excessive stress on the engine and increase the likelihood of failure. Avoid aggressive driving and modifications that could cause excessive heat and pressure in the engine.

  • Keep up with regular maintenance: Regular maintenance is key to preventing engine failure of any kind. Make sure you’re keeping up with oil changes, spark plug replacements, and other routine maintenance tasks.

  • Monitor your car’s performance: Keep an eye out for any warning signs of engine trouble, such as loss of power, unusual noises or vibrations, or changes in oil consumption. Catching potential issues early can prevent more costly repairs down the line.


Q: Is ringland failure covered under my Subaru warranty?

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A: It depends on the specific terms of your warranty. Some Subaru warranties do cover engine failure, while others may not. Check with your dealer or the Subaru website for more information.

Q: Can I prevent ringland failure by using a performance chip or tuning software?

A: While performance chips and tuning software can increase horsepower and torque, they can also put additional stress on the engine and increase the risk of ringland failure. If you’re considering modifying your car, make sure you understand the risks and take precautions to prevent engine failure.

Q: What are some common warning signs of ringland failure?

A: Some warning signs of ringland failure include loss of power, unusual noises or vibrations, changes in oil consumption, and smoking from the tailpipe.


Ringland failure is a serious issue for Subaru owners, and one that shouldn’t be taken lightly. While Subaru has made several changes to the 2019 STI engine to reduce the likelihood of this type of failure, it’s still important for drivers to take precautions to prevent it. By using high-quality fluids, avoiding aggressive driving and modifications, keeping up with regular maintenance, and monitoring your car’s performance for warning signs of trouble, you can help ensure that your Subaru engine stays healthy for years to come.

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Billy Covington

With a passion for all things automotive, Billy is our go-to expert on Subaru performance upgrades and modifications. He's been featured in several car magazines and blogs, and his extensive knowledge and expertise make him a valuable member of our team. When he's not working on cars, he enjoys playing guitar and writing music.

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