The Subaru WRX is an icon of Australian performance motoring, offering rally-bred all-wheel-drive traction and turbocharged boxer engine performance. While they are thrilling cars to own and drive, they come with a specific set of potential issues that prospective buyers and current owners need to watch out for.
EJ25 Ringland Failure (2008-2014 WRX & STI)
Perhaps the most infamous issue associated with the WRX, specifically models with the 2.5-litre EJ25 engine, is ringland failure. The ringlands are the small pieces of the piston that separate the piston rings. On the EJ25, these can be brittle and prone to cracking.
Symptoms
- A sudden loss of compression in one cylinder.
- A rough idle or engine misfire (often with a P030X code).
- Excessive oil consumption or "blow-by".
- Blue smoke from the exhaust.
The Cause
This is often attributed to the factory engine tune being too aggressive, combined with the cast nature of the stock pistons. Detonation (or engine knock) from low-quality fuel or overly aggressive driving can deliver a shockwave that cracks the fragile ringland. The solution is often a costly engine rebuild, typically with stronger forged pistons.
Oil Leaks from Gaskets
The boxer engine design, with its horizontally-opposed cylinders, has more gasket surfaces that can be prone to leaks as the car ages.
Common Leak Points
- Rocker Cover Gaskets: These are the most common culprits. Oil will drip from the bottom of the cylinder heads onto the hot exhaust manifold, causing a distinct burning oil smell.
- Oil Cooler Gasket: The gasket between the oil cooler (or heat exchanger) and the engine block can perish, leading to a significant leak.
- Crankshaft Seals: Both front and rear main seals can leak over time, a more labour-intensive job to fix.
Regularly checking under the car for drips and addressing any burning oil smells promptly is key to staying on top of these leaks.
Clutch and Throw-Out Bearing Noise
The manual transmissions in the WRX are generally robust, but the clutch components can be a source of noise and frustration.
Symptoms
- A chattering or squeaking noise when the clutch pedal is pressed.
- The noise disappears when the pedal is released.
- Difficulty engaging gears.
The Cause
This is almost always a worn or failing throw-out bearing (also known as a release bearing). While the part itself is not expensive, replacing it requires removing the entire transmission, making it a significant labour cost. Many owners choose to replace the entire clutch kit at the same time.
FA20DIT Engine Carbon Build-Up (2015+ WRX)
The newer WRX models (from 2015 onwards) use the 2.0-litre FA20DIT engine, which features direct injection. As with many direct-injection engines, this leads to carbon build-up on the intake valves over time, which can restrict airflow and hurt performance.
Symptoms
- Rough idle.
- Engine hesitation or stumbling under load.
- A gradual loss of power and fuel efficiency.
The Solution
The most effective way to clean the valves is walnut blasting. This is a maintenance item that should be considered every 80,000 to 100,000 kilometres to keep the engine running optimally.
The Subaru WRX is a high-performance machine that requires diligent maintenance. If you're experiencing an issue not listed here, use TorqueBot to get a more specific diagnosis for your car's symptoms.