2.4L DOHC Boxer Engine Assembly for 2024-2025 Subaru Ascent

A quick look at your own vehicle makes sure the right engine shows up:

• Check your VIN's 6th digit: Confirm that the 6th digit is 'A'.
• Verify your engine code: Confirm the engine code is FA24F (or FA24DIT) on the B-pillar or strut tower plate.
• Confirm your vehicle model: This engine is configured specifically for the Subaru Ascent (years 2024-2025).

What the install really takes — plan and budget with confidence:

Special tools this job needs:

• Subaru Engine Stand Adapter
• Crankshaft Pulley Wrench
• Fuel line disconnect tools for high-pressure direct injection lines
• Engine hoist
• Engine stand
• Comprehensive metric socket and wrench set
• Torque wrenches

Budget for these consumables at install:

• Engine Oil: 4.8 quarts of SAE 0W-20 Full Synthetic oil only
• Oil Filter: Genuine Subaru 'Black' oil filter (Tokyo Roki) or high-quality equivalent
• Coolant: Subaru Super Coolant (blue, pre-mixed)
• Spark Plugs: OEM Subaru/NGK Laser Iridium plugs (ILKAR8H6)
• Intake manifold gaskets
• Exhaust manifold / turbocharger inlet gaskets
• PCV valve and PCV hose assembly (highly recommended to install the updated design from TSB 11-204-23)
• Liquid gasket / RTV (ThreeBond 1217H or equivalent) for any resealing
• Accessory Belts (inspect and likely replace)

What your vehicle’s computers will need after the swap:

What’s involved: Throttle Body Calibration / Relearn, Crankshaft Position (CKP) Sensor Relearn, VVT (Variable Valve Timing) / AVCS Learned Values Reset, Idle Air Volume Relearn

sources differ on dealer_tool_required: one source states a dealer-level scan tool (SSM4) is required for CKP relearn, while another states it is strongly recommended but some high-end aftermarket tools may perform these functions. A dealer tool is the most reliable way to ensure proper initialization.

Pro tips for a smooth first start-up — hand them to whoever does the install:

• Excess RTV in the Oil Pan / Pickup Tube: Subaru uses a large amount of RTV silicone sealant on the oil pan and timing cover. Over time, excess RTV squeezes out, cures, breaks off, and gets sucked into the oil pickup tube screen, causing oil starvation and engine failure. You must drop the lower oil pan and inspect/clean the oil pickup tube screen before installing this engine.
• Turbocharger Transfer: Since this engine is sold 'LESS TURBO', you must transfer your original turbocharger. Ensure the oil feed and return lines are completely flushed of any metal debris from the previous engine failure.
• Torque-to-Yield (TTY) Bolts: The harmonic balancer (crankshaft pulley) bolt and the flywheel/flexplate bolts are torque-to-yield and must be replaced with new OEM fasteners. Do not reuse them.
• Rocker Arm Displacement: If you remove the camshaft carriers or valve covers for any reason, be extremely careful. The rocker arms on the FA24 are not physically secured to the pivots and can easily fall out of place into the oil galleries.
• Ground Straps: Pay meticulous attention to all engine and transmission ground straps. Missing or poorly connected grounds are a common cause of bizarre electrical issues, no-start conditions, and sensor errors after an engine swap.
• Fragile Sensors and Connectors: The plastic connectors for sensors and the wiring harness can become brittle with heat and age. Handle them with care to avoid breakage.

Easy to get right once you know them:

• Reusing a contaminated oil cooler or turbocharger without a meticulous flush or replacement.
• Ordering for a non-Ascent vehicle (such as WRX, Outback XT, or Legacy XT) assuming they are interchangeable.
• Using the wrong oil weight (stick to 0W-20 to prevent AVCS malfunction).
• Ignoring oil pan leaks and failing to reseal the oil pan while the engine is out of the vehicle.
• Skipping essential sensor and idle relearn procedures post-install.

Not issues with the units on this page — the manufacturer documented these for every engine of this family, wherever you buy one. Handy for your installer: