Subaru began making the WRX in 1992 and they remain in production today. The name “WRX” stands for “World Rally eXperimental” in honor of their rally heritage. Subaru WRX & STI models use rally inspired tech like AWD, stiff suspension, and turbo 4-cylinder engines. This makes the WRX a popular car in the racing and tuning world. There’s not question the WRX is a fun, sporty car. However, does that come at the cost of less reliability? In this guide, we discuss Subaru WRX & STI reliability and common engine problems.
*It’s also known as the Impreza WRX. However, Subaru dropped Impreza from the name for model year 2015 and beyond.
Subuaru WRX Over the Years
Before we dive into the meat of this article there are a few important notes. WRX models have been around for nearly 30 years. So far it’s spanned 4 chassis generations. There are also a handful of different engines powering WRX & STI models over the years. Below is a list of those engines:
- EJ20G (1992-1998)
- EJ20K (1996-1998)
- EJ205 (1999-2006)
- EJ255 (2006-2015)
- FA20F (2015-present)
- EJ257 (2004-present) STI models only
We’ll discuss non-engine reliability, but our primary focus is on the WRX engines. Over time, we’ll have a guide to each specific engine (with links above). In this article, we’ll mostly focus on a few problems that are shared among many WRX’s. Some years and models will be more or less reliable than others.
Impreza WRX Tuning, Mods
Part of what we’re discussing in this article ties into the nature of the WRX & STI engines tuning capability. With their rally inspired build and turbo engines it’s easy to get more out of these Subaru’s. Mods and tuning are commonplace. Many WRX’s are capable of picking up 50-100+ horsepower with a tune and basic bolt-on mods. Throw on a turbo upgrade and the WRX/STI engines can make even more power.
Along with that generally comes owners who drive and push their cars harder. Often, we find these same owners are also pretty good at staying on top of maintenance. As such, there can be a little bit of a balancing effect. Regardless, increasing power on a stock engine does increase the chances of something going wrong.
Effects on Reliability
This is no dig at Subaru owners since this occurs on any easily tuned engine. We see it all the time in the BMW world. Less experienced owners might throw on a poor tune and cheap bolt-ons without fully understanding engines and tuning. They try to get every ounce of power out of the engine rather than playing it safe and conservative. This can certainly have negative effects on Subaru WRX / STI reliability.
With a conservative tune, proper supporting mods, maintenance, and data-logging it can be a very safe setup. In these cases there should be relatively minimal effects to reliability or longevity. Point is – beware who you’re buying a WRX from and how they may have treated and tuned the car in the past.
Subaru WRX Common Engine Problems
With some background info out of the way let’s finally dive into the bulk of this article. Below are a few of the most common problems with the Subaru WRX and WRX STI:
- Engine internals
- Turbo failure
- Oil leaks
We’re calling these the most common problems for a reason. It doesn’t necessarily mean the problems are common and affect a large percentage of WRX’s. Rather, when issues do occur these are a few of the common areas. Also, some of these failures may be more common on certain years and engines. However, they do affect nearly all Subuaru WRX engines to some degree.
We’ll dive into each of the above WRX/STI engine problems and finish the article with overall thoughts on reliability.
1) WRX & STI Internal Engine Failures
There are lots of internal moving parts on an internal combustion engine that can fail. They’re serious problems that are costly at best and may result in complete engine failure. Unfortunately, the WRX and STI engines haven’t earned the best reputation for internal strength. However, it’s rarely a problem on completely stock engines. WRX internal engine problems are more likely to occur when tuned and modded. A few known weak points include:
- Rod bearings
- Piston rings
These issues appear most common on the 2004+ EJ255, EJ257, and FA20 engines. There have even been some lawsuits regarding internal engine issues on these engines. However, all Subaru WRX and STI engines may run into these problems.
If you plan to tune and mod the WRX ensure you’re sticking with a proper, conservative tune. Pre-detonation is usually the underlying cause of internal engine damage. You want to make sure your engine isn’t running lean, experiencing significant timing pulls, etc.
Subaru Internals Upgrades & Replacement
One way to mitigate risks is to upgrade the pistons, rods, and/or bearings. It’s a costly process to do this, and usually isn’t worth the price unless you plan to make lots of power (350-400+whp). However, the stock internals can and do let go at stock power and even with modest tunes. In these cases the repair bills can quickly add up to $2,000+. It’s also not too uncommon for internal failures to wipe out the entire engine.
2) Subaru WRX Turbo Problems
The above internal problems are a little more common on the newer WRX engines. On the other hand, turbo problems are more likely to affect older models. Turbo technology has come a long way in the last 10-15 years. They weren’t quite as reliable back in the day and turbo lifespan was generally shorter. That said, a lot of older Subaru WRX’s may have already had the turbo replaced.
Otherwise, turbo problems become more common when tuning and modifying the WRX and WRX STI models. The increase in power usually comes from running more boost. This can put a lot of extra stress on the stock turbo. Proper supporting mods can go a long way in helping with turbo longevity.
One final point – turbos are moving parts subject to wear and tear. At peak boost they can run at speeds near or beyond 150,000 RPM’s. Failures due to natural wear aren’t uncommon north of 120,000 miles. Modern turbos can sometimes last nearly twice that long, though.
3) Subaru Oil Leaks
Oil leaks are a very general problem. Engines have many various gaskets and other parts that may cause oil leaks. Most Subaru WRX & STI models will run into an oil leak at some point in their lives. A few common areas where leaks may occur include:
- Valve cover gaskets
- Oil pan gasket
- Main seals
None of these are super common issues on any of the Subaru WRX engines. However, gaskets are subject to wear and tear over time. It’s probably not fair to call oil leaks a true problem since it’s usually natural for aging engines to develop leaks. Nonetheless, if you’re looking to own an older WRX or keeping a newer one for the long-term then you may run into a small oil leak or two.
4) Subaru WRX Misfire Issues
Another somewhat vague problem here. WRX misfires are rarely an issue themselves. Rather, misfires indicate there’s another underlying problem with the engine. It’s common stuff on turbo engines since they like to burn through spark plugs and ignition coils rather quickly. That’s just basic maintenance so we don’t think it’s fair to necessarily call them problems. If your Subaru WRX/STI is experiencing misfires consider the following parts:
- Spark plugs
- Ignition coils
- Fuel injectors
- Carbon build-up
Spark plugs and ignition coils are without question two of the most common causes of WRX misfires. Leaking or faulty injectors may also cause misfires. Finally, newer direct injection (DI) Subaru engines can have misfires due to excess carbon build-up. Carbon build-up usually isn’t a problem on the WRX until close to 100,000 miles. It’s standard maintenance on DI engines since there isn’t any fuel flowing over intake valves to clean them.
Subaru WRX Reliability
Is the Subaru WRX and WRX STI reliable? Yes and no. These engines often don’t earn the best regards for reliability compared to lower performance Subaru engines. However, it makes sense. Performance cars and turbocharged engines are generally a little more demanding. This is especially true when there’s a lot of tuning and aftermarket potential. A lot of Subaru WRX models end up with mods at some point in their lives. Even when done right it can still increase the overall stress the engines are subject to.
Point is – the WRX isn’t a reliable car compared to many non-performance cars on the road. However, it’s fairly reliable when you consider turbo engines and performance cars are more demanding. Spark plugs and ignition coils wear down faster. Suspension wears down faster. Turbos add a lot of extra parts and areas for potential problems. It’s simply part of the nature of owning a rally/race inspired car like the Subaru WRX and WRX STI.
If you plan to tune and mod the car then stick on the conservative side, or upgrade the internals. Use high quality oils, stay on top of maintenance, and fix problems when they occur. Do all of this and the Subaru WRX can be a pretty reliable car and engine.