These 4-Cylinder Subaru Engines Have A Bad Reputation For A Good Reason

Subaru is generally considered a reliable brand, claiming the second spot in Consumer Report’s 2025 vehicle reliability ratings. But not all Subaru engines are built the same, and the EJ engines in particular have an especially poor, and well deserved, reputation. We’ve previously covered issues with head gasket leaks on Subaru’s 2.5-liter EJ engines, an issue that was so prevalent it became a running joke, in large part because of the company’s muddled response. Unfortunately, that’s the tip of the iceberg in terms of mechanical and technical failures plaguing the EJ lineup.

For instance, Subaru was forced to issue a warranty extension in March 2019 because of an issue that caused crankshaft bearing failures on some EJ engines, specifically those in the 2012–2014 WRX and 2012–2017 STI. EJ engines have also classically suffered bearing damage from oil starvation, contamination, or incorrect bearing clearances.

A major culprit is the factory oil pickup, the “drinking straw” assembly that feeds oil from the engine’s oil pan to its oil pump. Cracks can begin to develop around the pickup’s brazed joint, allowing air into the oil supply and compromising pressure, which can speed up wear and tear. In some cases, a sudden oil pressure loss may even cause immediate engine failure.

The head gasket problem shouldn’t be discounted and is a common issue among some of Subaru’s boxer engines, the layout that the EJ platform is built around. But there are a number of other problems that can lead to EJ breakdowns, some of which can be attributed to poor maintenance rather than intrinsic design.

One vulnerability that often rears its head after the engine has already suffered some kind of internal damage is contamination. Even if you replace broken parts, you’re not necessarily fully removing all the metal particles they released when they were damaged. This kind of debris can still be floating around inside oil passages, cam gears, or components of the Active Valve Control System.

The AVCS uses engine oil to adjust camshaft timing, and contamination can obstruct smaller passages and interfere with the process. This can, in turn, lead to inconsistent power, rough idling, or hesitation. It may also mean expensive inspections of contaminated components and cleaning out oil passages, or having to pay to replace parts beyond those that were originally damaged.