Are Subaru turbos water-cooled?
Yes. Subaru factory turbochargers are water-cooled—the center section of the turbo is cooled by the engine's coolant loop while lubrication comes from the oil system. This dual cooling approach helps manage heat during sustained boost and is standard on Subaru's modern turbocharged engines.
How Subaru cools its turbochargers
Subaru's modern turbos use a water-cooled center housing rotating assembly (CHRA). Coolant lines route from the engine's cooling system to the turbo, absorbing heat from the cartridge and returning to the radiator circuit. The turbo's bearings and oil flow provide lubrication and additional heat removal; many setups also include an oil cooler to maintain oil temperature under boost.
Before delving into the specifics, here is a concise description of the cooling approach used by Subaru turbochargers:
- Water-cooled center housing: The CHRA is cooled by engine coolant circulating through dedicated lines to the turbine bearing area.
- Oil-based lubrication with cooling: Engine oil lubricates the bearings and helps carry away heat; some units include an integrated or separate oil cooler.
- Thermal management via intercooling and exhaust design: The overall system is designed to minimize turbo heat load, with intercoolers and exhaust routing playing a role.
Understanding these components clarifies how Subaru maintains turbo reliability under dynamic driving conditions.
Maintenance considerations
Maintaining the coolant and oil systems is essential for turbo reliability in Subaru vehicles with factory turbos. The following points cover typical maintenance tasks and checks.
- Check coolant level and hoses: Ensure the coolant is at the correct level and inspect lines for cracks or leaks that could affect turbo cooling.
- Inspect turbo coolant lines for leaks or damage: Damaged lines can lead to overheating and turbo failure if coolant stops flowing.
- Monitor oil health: Regular oil changes with the correct viscosity and quality help protect the turbo bearings and assist in cooling via oil flow.
- Look for overheating symptoms: Unusual engine temperature rise, white smoke from exhaust, or coolant loss may indicate turbo cooling issues.
Regular checks on coolant and oil systems are key to preventing turbo-related failures in Subaru vehicles.
Exceptions and aftermarket considerations
While Subaru's modern factory turbochargers are generally water-cooled, some aftermarket turbochargers or legacy setups may use different cooling schemes, including oil-only or air-cooled options. Always verify the cooling design of a specific turbo when replacing or upgrading a turbo to ensure compatibility with your vehicle's cooling system.
Summary
Subaru’s current turbochargers are typically water-cooled, using engine coolant to cool the center cartridge and bearing area while relying on oil for lubrication and helping carry away heat. This arrangement supports higher boost levels and durability in daily driving and performance scenarios. Regular maintenance of the coolant and oil systems is essential for long-term turbo reliability.
How to tell if a turbo is water-cooled?
If the turbocharger's center housing has threaded ports on either side, at 90° from the oil inlet/outlet flanges, then it is water-cooled.
How reliable is the Subaru 2.4 L turbo engine?
Subaru's 2.4-liter turbocharged engine has been known to last over 150,000 miles with routine maintenance. All of the issues mentioned here can be avoided entirely with proper care. This makes this engine hard to beat.
How are Subaru turbos cooled?
The main components of a Subaru turbocharger system are a water-cooled turbocharger, an air-cooled intercooler, a wastegate control solenoid valve, sensors and a controller.
Are Subaru engines water-cooled?
All of Subaru's four-cylinder engines (except the EN series) are liquid-cooled, horizontally opposed boxer four-strokes.
