Can Subaru engines be rebuilt?

Yes. Subaru engines can be rebuilt, including the well-known EJ and the newer FA/FB boxer engines. Rebuilding is a common option for high-mileage or damaged engines, though feasibility and cost depend on the specific engine family, the extent of damage, and the availability of parts and skilled labor.

Rebuilding a Subaru engine involves diagnosing the problem, disassembling the motor, machining as needed, sourcing parts, and carefully reassembling with correct tolerances and break-in procedures. This guide explains which engines are typically rebuilt, what the process entails, cost considerations, and practical decision points for owners weighing repair versus replacement.

Engine families commonly rebuilt

Among Subaru’s lineup, three engine families are most often rebuilt by shops and enthusiasts. Each family has its own strengths, common failure modes, and parts availability.

• EJ series (2.0L/2.5L, older and widely used): This venerable boxer engine is the most frequently rebuilt Subaru powerplant, especially its 2.5L variants known for head-gasket and bearing wear at high mileage. Availability of rebuild kits and aftermarket support is robust, making it a practical choice for many shops and DIYers.


• FA/FB series (modern 2.0L/2.5L boxer engines): These newer, direct-injected engines are common in late-model Subarus. They can be rebuilt, but the direct injection system, carbon buildup on intake valves, and newer componentry add complexity. Parts availability is good, but some DI-specific issues require more specialized service.


• EZ series (3.0L/3.6L, used in select models): Less common than EJ/FA/FB, but rebuildable. Availability of factory-style parts and machine work is more limited, so pricing and lead times can vary by region.

For each engine family, the decision to rebuild versus replace often hinges on damage extent, core availability, and the intended lifespan of the vehicle. Rebuilding remains a viable path for many Subaru owners, especially when a vehicle has solid residual value and the required expertise is accessible.

What does a rebuild involve?

The rebuild process shares core steps across engine families, but DI engines and boxer layouts introduce particular considerations. The following outline summarizes the typical workflow.

1. Assessment and planning: Diagnose the root cause, confirm compression and leak-down results, and decide whether a rebuild or a replacement is most economical.


2. Disassembly and inspection: Remove the cylinder heads, oil pan, and major components; measure wear (piston/cylinder bore, main/rod bearings, valve seats, head gasket surfaces) to determine machining needs.


3. Machining and parts preparation: Machine the cylinder bores if needed, resurface heads if required, and prepare mating surfaces. DI engines may require additional cleaning for carbon buildup on intake valves.


4. Parts replacement and reassembly: Install pistons, rings, bearings, seals, gaskets, timing components (belts or chains and tensioners), oil pump, and water pump as dictated by the rebuild plan.


5. Timing and servicing: Set timing accurately, verify valve clearance where applicable, and replace components that wear out in service (e.g., timing chains, tensioners, cam seals).


6. Fluids, initial startup, and testing: Prime the engine with proper oil, perform a cautious break-in, and run compression and leak-down tests. Monitor for leaks, unusual noises, or abnormal temperatures during the initial run.

Note: Direct-injection (DI) FA/FB engines introduce added tasks such as carbon cleaning of intake valves and potential fuel-system considerations. That extra work can influence both the timeline and the cost of a rebuild.

Costs and feasibility

Costs for rebuilding a Subaru engine depend on the engine family, the extent of damage, the labor rate in your area, and whether you use OEM, aftermarket, or remanufactured components. The following points give a rough sense of what owners typically encounter.

• Typical parts and machining: A basic rebuild on an EJ engine might range from a few thousand dollars to around $5,000–$7,000, depending on scope. FA/FB rebuilds can be similar or higher due to DI-related work and newer parts. EZ engines fall within a comparable range, though regional availability affects pricing.


• Labor and shop rates: Labor costs vary regionally, but expect a significant portion of the total price to cover skilled disassembly, machining, and precise reassembly. In many areas, labor can account for 40–70% of the total bill.


• Remanufactured long blocks and alternatives: Some shops and suppliers offer remanufactured short or long blocks with warranties, which can be cost-competitive when compared to a full rebuild. Installing a remanufactured unit may reduce labor time and provide a reliable baseline.


• When to consider replacement: For engines with extensive damage, severe core issues, or high mileage on a vehicle with low resale value, many buyers opt for a used engine, a remanufactured block, or a complete replacement as a more predictable risk management strategy.

Ultimately, the decision to rebuild depends on damage severity, part availability, potential warranty, and how long you plan to keep the vehicle. For some owners, a rebuild offers the best balance of cost and longevity; for others, replacement may be the smarter financial move.

Summary

Subaru engines can be rebuilt across multiple families, with the EJ, FA/FB, and EZ engines being the most commonly addressed by specialists. The process is technically feasible but varies in complexity and cost, especially for direct-injected FA/FB units. A rebuild requires careful diagnosis, precise machining, and adherence to Subaru’s torque and timing specifications, along with a clear assessment of whether rebuilding or opting for a remanufactured block or a used engine provides better long-term value. For many owners, informed planning with a trusted shop is the key to choosing the right path and ensuring reliability after the rebuild.

How much is it to rebuild a Subaru engine?

A Subaru engine rebuild typically costs $5,000 to $10,000 or more, with the final price depending on the engine's condition, the parts needed, and labor costs. Costs can range from approximately $2,500-$4,000 for parts and machine work alone for simpler builds to over $15,000 for high-performance builds. 
Factors that influence the cost

• Parts: You'll need to purchase parts like a new short block, full gasket kit, bearings, rings, and potentially upgraded components like pistons and head studs. 
• Machining: A critical and often costly part of the process is engine machining, which is essential for Subarus to ensure proper alignment and prevent distortion. 
• Labor: Labor costs for both the teardown and reassembly are significant, often adding several thousand dollars to the total. 
• Performance upgrades: Building an engine for higher horsepower will require more expensive parts and potentially more extensive machining, driving the price up considerably. 
• Dealer vs. independent shop: Dealerships typically have much higher labor rates than independent Subaru specialists or a trusted mechanic. 

Cost breakdown examples

• DIY/budget rebuild: A basic rebuild with a new short block, machine work, and a full gasket set could cost around $4,100 in parts and machine shop labor. 
• Professional rebuild: A more comprehensive rebuild, including high-performance parts and professional labor, can easily reach $8,000 to $10,000 or more. 
• High-performance rebuild: If you're aiming for 500 horsepower or more, expect to spend upwards of $15,000 or more on parts and labor alone. 

Alternative options

• Engine replacement: A new or remanufactured Subaru engine can range from $3,000 to $5,000 or more, depending on the model and whether you use OEM or aftermarket parts. However, this doesn't account for labor, which can also add several thousand dollars to the total.
• Used engine: While cheaper, a used engine from a junkyard or private seller comes with a risk, as you don't know its history or condition. 

Is it cheaper to rebuild or get a new engine?

Rebuilding an engine is often cheaper upfront than a full replacement, but replacement can be a better long-term investment, especially if a used or remanufactured engine comes with a warranty. The final cost depends on the extent of the damage, the vehicle's age and type, and the labor involved. 
Engine Rebuild

• Pros:
  • Lower initial cost: A rebuild is generally less expensive than buying a new or remanufactured engine, with costs often ranging from $2,500 to $4,500. 
  • Keeps original engine: This can be valuable for certain vehicles and may help retain its overall value. 
  • Can improve performance: A proper rebuild can restore and even improve the engine's performance and fuel economy. 
• Cons:
  • Hidden costs: The price can increase significantly if the initial inspection fails to identify deeper, more expensive damage that is discovered once the engine is disassembled. 
  • No warranty: Rebuilt engines may not come with a warranty, or the warranty may be limited. 
  • Time-consuming: A rebuild takes time, and you may need to account for rental car costs if you need transportation while the work is being done. 

Engine Replacement

• Pros:
  • More reliable: A new or remanufactured engine often comes with a warranty, providing a safety net and peace of mind. 
  • Less risky: A replacement engine is a fully functional unit, avoiding the risk of discovering more damage during the rebuild process. 
• Cons:
  • Higher upfront cost: The initial price is steeper, with costs ranging from $4,000 to over $8,000, depending on the engine type. 
  • Used engine gamble: A used engine can lower the cost, but it also carries the risk of unknown history and potential future problems. 

Which option is right for you?

• Choose a rebuild if: The engine damage appears minor, you want the most cost-effective option upfront, and you are willing to accept a higher risk of additional costs.
• Choose a replacement if: The engine is severely damaged, you prioritize long-term reliability and a warranty, and you are willing to pay more for peace of mind. 

What is the average lifespan of a Subaru engine?

200,000 miles
Engine Lifespan: Subaru engines are known for their durability and longevity, with many drivers reporting engines that last well beyond 200,000 miles with proper maintenance. The key to extending the lifespan of your Subaru engine is regular maintenance, including oil changes, fluid checks, and tune-ups.

Are Subaru engines expensive to fix?

The cost to replace a Subaru engine can vary depending on factors such as the model year, engine type, and labor costs. On average, the cost to replace a Subaru engine can range from $3,000 to $5,000 or more, including parts and labor.