2.4L 4-Cylinder Boxer Engine Long Block for 2023 Subaru Ascent

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

• Confirm the 6th digit of your 17-digit VIN is 'A'.
• Verify the engine model listed on the driver's side B-pillar door jamb or strut tower is FA24F (or FA24DIT).
• Confirm your vehicle is equipped with the Lineartronic CVT automatic transmission.

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

Special tools this job needs:

• Engine hoist
• Heavy-duty load leveler
• Subaru-specific engine stand adapter plate (or extra-long grade-8 bolts)
• Thin-profile 12mm and 14mm flex-head wrenches or sockets
• High-quality RTV sealant (Subaru ThreeBond 1217H)
• Fuel line disconnect tools
• Torque wrenches

Budget for these consumables at install:

• 5.2 quarts of synthetic 0W-20 engine oil (API SP / ILSAC GF-6 spec)
• New OEM Subaru oil filter
• Subaru Super Coolant (pre-mixed blue formula)
• New intake manifold gaskets
• New exhaust manifold gaskets
• New turbocharger mounting gaskets and copper crush washers
• Rear main seal
• Fresh set of NGK Laser Iridium spark plugs

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

What’s involved: Crankshaft Position (CKP) System Relearn, Throttle Body Idle Air Volume Relearn, Camshaft Position (CMP) / AVCS Relearn, and Immobilizer/ECU Re-marriage

sources differ: Arm 1 states no ECU re-marriage is required but sensor relearns are mandatory; Arm 2 states an immobilizer and ECU re-marriage procedure is highly likely to make the new engine communicate with the vehicle's immobilizer and BIU. A professional-grade, bi-directional diagnostic scan tool (such as the Subaru Select Monitor SSM4) is required.

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

• Torque Converter Bolt Access: Accessed through a small opening at the top rear of the engine block on the passenger side covered by a black rubber plug. Rotate crankshaft by hand to access each bolt. Do not drop bolts into the transmission bell housing.
• Liquid Gasket (RTV) Application: Apply RTV sparingly and precisely. Excess RTV can break off into the oil pan and clog the oil pickup tube screen, causing oil starvation.
• CVT Alignment Precautions: Ensure the torque converter is fully seated into the transmission fluid pump before mating the engine to the transmission to avoid crushing the pump.
• Turbocharger Transfer: Pay close attention to the condition of the oil feed and return lines. Clean and inspect all related components to prevent debris from destroying the replacement engine.
• Direct Injection System: Be extremely careful with high-pressure fuel lines and injectors. Ensure the system is properly depressurized before working on it.
• Carbon Buildup: Inspect and clean the intake ports and valves while the engine is out.
• Engine/Transmission Separation: Separating the dowel pins and torque converter can be difficult. Take care not to damage the torque converter or transmission input shaft.
• Grounding Straps: Pay meticulous attention to all grounding strap locations to avoid electrical issues and no-start conditions.

Easy to get right once you know them:

• Reusing Old Turbo Gaskets and Hardware: Reusing old metal gaskets or copper crush washers on turbo oil and coolant feed lines leads to immediate leaks.
• Failing to Clean or Replace the Oil Cooler: If the original engine suffered catastrophic internal failure, metal debris trapped inside the oil cooler will wash into the new engine and destroy it.
• Using the Wrong Oil Weight: Using heavier oil (like 5W-30 or 10W-30) instead of the specified 0W-20 can restrict oil flow to AVCS solenoids and trigger timing-related DTCs.
• Skipping the Crankshaft Relearn: Neglecting the CKP relearn results in false misfire codes (P0300-P0304) and a flashing check engine light.
• Incorrect Harness Usage: Using the donor engine's wiring harness instead of the vehicle's original harness can cause compatibility problems with body electronics.
• Skipping the ECU Re-marriage: Assuming the engine is plug-and-play without planning for electronic re-marrying to the car's security system.

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: