Subaru OEM EJ253 Shortblock (08 - 11 Impreza) | 10103AB820

Overview

The Genuine Subaru OEM EJ253 Short Block Assembly (Part #10103AB820) is a factory-direct replacement engine short block designed for 2008–2011 Subaru Impreza models equipped with the 2.5L EJ253 naturally aspirated horizontally opposed (boxer) four-cylinder engine. This is the definitive solution for engine rebuilds, bottom-end failures, spun bearings, or severe internal engine damage — delivering the exact-fit precision and factory-grade quality that only a genuine OEM assembly can provide. If you need to restore your Impreza's engine to like-new condition without compromise, this is the correct part.

Key Features & Benefits

• Genuine Subaru OEM Quality — Manufactured to Subaru's exact factory specifications; not a remanufactured or aftermarket unit. Ensures correct tolerances, materials, and assembly standards right out of the box.
• Exact-Fit Guarantee — Engineered specifically for the EJ253 application in 2008–2011 Impreza. Direct bolt-in replacement with no modifications required to engine bay, mounts, or ancillary components.
• Complete Short Block Assembly — Includes the machined cylinder block, crankshaft, connecting rods, pistons, piston rings, and main/rod bearings assembled and clearanced at the factory.
• Factory Warranty Eligible — As a genuine Subaru OEM part, this assembly is backed by Subaru's standard OEM parts warranty when installed by an authorized technician.
• Restored Engine Integrity — Restores proper compression, oil pressure, and bottom-end strength to factory specifications, extending the service life of your Impreza's powertrain.
• Correct Subaru Part Number — Genuine part number 10103AB820 ensures you receive the exact correct assembly with no guesswork or cross-referencing errors.

What's Included

• 1x Genuine Subaru OEM EJ253 Short Block Assembly
• Assembled cylinder block with crankshaft, connecting rods, pistons, rings, and bearings
• Factory assembly per OEM tolerances and specifications

Specifications

Fitment & Compatibility

This genuine Subaru OEM short block assembly is designed for the following vehicles:

Important: Verify your vehicle's VIN and engine code before ordering. This short block is specific to the EJ253 naturally aspirated engine. It is NOT compatible with EJ255 (WRX turbocharged) or EJ257 (STI turbocharged) applications. When in doubt, cross-reference Subaru part number 10103AB820 with your dealer parts catalog or VIN lookup.

Installation

Short block replacement is a major engine repair requiring full disassembly of the engine top end, removal of all accessory components, and proper torque sequencing during reassembly. All external components from the original engine — including the cylinder heads, camshafts, timing components, oil pump, water pump, intake, and exhaust manifolds — must be transferred to or replaced on this new short block. Professional installation by a qualified Subaru technician or experienced engine builder is strongly recommended. Proper break-in procedures should be followed after installation to ensure long-term durability and to maintain warranty eligibility.