The 2004 Subaru Impreza came with a 2.5-liter SOHC flat-four engine, producing 165 horsepower and 166 lb-ft of torque. This naturally aspirated boxer engine features Subaru’s signature horizontally-opposed cylinder layout, providing a lower center of gravity and better balance. The engine uses a timing belt system that requires replacement every 105,000 miles along with the water pump and tensioners. It’s paired with either a 5-speed manual or 4-speed automatic transmission and comes standard with Subaru’s symmetrical all-wheel drive system, making it capable in various weather conditions while delivering decent fuel economy.

The 2004 Subaru Impreza shares most parts with the 2002-2007 second-generation Impreza models. Engine components from the 2.5L SOHC are largely interchangeable across these years, including intake manifolds, cylinder heads, and most sensors. Body panels and interior components are compatible within the 2002-2007 range, though minor trim differences exist between model years. Suspension components, brakes, and drivetrain parts also interchange well within this generation. Some electrical components and ECU modules may have year-specific programming requirements, so verification is recommended for complex electronic parts.

Parts availability changes daily. Call us at (603) 392-7313 or visit our online shop to check current inventory from this specific vehicle. If we have sold a part you need, our Parts Broker service can source it from our network of partner yards nationwide.

Yes! We ship parts from this vehicle and our entire inventory nationwide. Most orders ship within 1-2 business days via FedEx or freight carriers for larger components like engines and transmissions. Call (603) 392-7313 for a shipping quote on any part.

The 2.5L SOHC engine in the 2004 Impreza is moderately reliable but has well-documented issues, primarily head gasket failures that typically occur between 80,000-120,000 miles. Once the head gaskets are properly replaced with updated multi-layer steel gaskets, the engine can be quite dependable. Regular maintenance is crucial, including timely timing belt replacement every 105,000 miles and using quality coolant to prevent corrosion. The engine responds well to regular oil changes and can easily reach 200,000+ miles when properly maintained and the head gasket issue is addressed proactively.