Best Used Engines for Subaru: Outback, Forester, Impreza & More

Best Used Engines for Subaru: Outback, Forester, Impreza & More

Finding the Right Replacement Engine for Your Subaru

Subaru has built a devoted following with their unique boxer engines, legendary all-wheel drive, and rugged reliability. When a Subaru engine fails—often due to the infamous head gasket issue—finding the right replacement means understanding Subaru's distinctive engine technology and what makes them special.

At Used Engines Store, we specialize in matching Subaru owners with quality, tested engines that deliver the reliability and AWD capability Subaru is known for. Here's your complete guide to replacing your Subaru engine.

Popular Subaru Engine Options by Model

Subaru Outback Engines

2.5L Boxer 4-Cylinder (EJ25) - Most Common

  • Available: 2000-2012
  • Power: 165-173 hp
  • Known for: Smooth boxer design, AWD capability
  • Lifespan: 150,000-200,000 miles (with head gasket replacement)
  • Common issues: Head gasket failure (100,000-150,000 miles), oil consumption

2.5L Boxer 4-Cylinder (FB25) - Newer Generation

  • Available: 2013-Present
  • Power: 175-182 hp
  • Known for: Improved head gasket design, better fuel economy
  • Lifespan: 200,000-250,000+ miles expected
  • Common issues: Oil consumption (early models), CVT compatibility

3.6L Boxer 6-Cylinder (EZ36)

  • Available: 2010-2019
  • Power: 256-260 hp
  • Known for: Smooth power, no head gasket issues, towing capability
  • Lifespan: 200,000-250,000+ miles
  • Common issues: Minimal—most reliable Subaru engine

Subaru Forester Engines

2.5L Boxer 4-Cylinder (EJ25)

  • Available: 1998-2013
  • Power: 165-173 hp
  • Known for: Proven design, AWD capability
  • Lifespan: 150,000-200,000 miles
  • Common issues: Head gasket failure (same as Outback)

2.5L Boxer 4-Cylinder (FB25)

  • Available: 2014-Present
  • Power: 182 hp
  • Known for: Improved reliability over EJ25
  • Lifespan: 200,000-250,000+ miles expected
  • Common issues: Oil consumption (early models)

2.0L Turbo Boxer 4-Cylinder (FA20DIT)

  • Available: 2014-2018 (Forester XT)
  • Power: 250 hp
  • Known for: Strong performance, direct injection
  • Lifespan: 150,000-200,000 miles
  • Common issues: Carbon buildup (direct injection), turbo complexity

Subaru Impreza/WRX Engines

2.0L Boxer 4-Cylinder (EJ20)

  • Available: 2002-2005 (WRX)
  • Power: 227 hp (turbocharged)
  • Known for: Legendary WRX performance, tuner favorite
  • Lifespan: 150,000-200,000 miles (if not modified)
  • Common issues: Head gasket failure, ringland failure (modified engines)

2.5L Turbo Boxer 4-Cylinder (EJ255/EJ257)

  • Available: 2006-2014 (WRX/STI)
  • Power: 265-305 hp
  • Known for: High performance, rally heritage
  • Lifespan: 100,000-150,000 miles (performance use)
  • Common issues: Ringland failure, head gasket issues, turbo failures

2.0L Boxer 4-Cylinder (FB20)

  • Available: 2012-Present (Impreza)
  • Power: 148-152 hp
  • Known for: Fuel efficiency, reliability
  • Lifespan: 200,000+ miles expected
  • Common issues: Oil consumption (early models)

The Infamous Subaru Head Gasket Problem

The #1 issue with Subaru engines: head gasket failure on EJ25 engines (2000-2012).

What happens:

  • Head gaskets fail between 100,000-150,000 miles
  • Coolant leaks externally (visible under engine)
  • Oil and coolant can mix (catastrophic)
  • Overheating if coolant loss is severe

Why it happens:

  • Original gasket design flaw
  • Boxer engine design puts stress on gaskets
  • Horizontal engine layout causes uneven pressure

Symptoms:

  • Coolant puddles under car
  • Sweet smell from engine bay
  • Overheating
  • White smoke from exhaust (if internal leak)
  • Milky oil (if coolant mixing with oil)

Cost to fix (without engine replacement):

  • Head gasket replacement: $1,500-$2,500
  • Timing belt (done at same time): $400-$800
  • Water pump: $200-$400
  • Total: $2,100-$3,700

When to replace engine instead:

  • If engine has overheated severely
  • If oil and coolant have mixed (internal damage)
  • If engine has high mileage (180,000+) and other issues
  • If head gasket has failed multiple times

Pro tip: When buying a used EJ25 engine, verify head gaskets have been replaced with updated gaskets, or buy a newer FB25 engine that doesn't have this issue.

Why Subaru Boxer Engines Are Unique

Subaru's horizontally-opposed "boxer" engine design is different from all other manufacturers:

What is a boxer engine?

  • Cylinders lay flat, opposing each other horizontally
  • Pistons "punch" outward like boxers (hence the name)
  • Lower center of gravity than traditional inline or V engines

Advantages:

  • ✅ Lower center of gravity (better handling)
  • ✅ Naturally balanced (smooth operation)
  • ✅ Compact design fits AWD system perfectly
  • ✅ Better weight distribution

Disadvantages:

  • ❌ More complex to work on (horizontal layout)
  • ❌ Higher labor costs for repairs
  • ❌ Head gasket stress (EJ engines)
  • ❌ Oil consumption issues (some models)

Should You Replace With the Same Subaru Engine?

Yes—always stick with your original Subaru engine type.

Why same-engine replacement is critical for Subarus:

  • AWD system is calibrated for specific engine
  • Computer systems are VIN-specific and highly integrated
  • CVT transmission programming matches specific engine
  • Emissions compliance (especially California)
  • Maintains Subaru's unique driving characteristics
  • Preserves resale value

Engine swaps in Subarus are complex and expensive:

  • Custom wiring harnesses: $800-$2,500
  • ECU swap or reprogramming: $1,000-$3,000
  • AWD system compatibility: $500-$2,000
  • Transmission issues: May need different transmission
  • Emissions certification: Difficult in most states
  • Total swap cost: $4,000-$10,000+

Our recommendation: Replace with the exact engine your Subaru came with. It's reliable, cost-effective, and maintains your vehicle's legendary AWD capability.

Common Subaru Engine Problems by Type

EJ25 2.5L (2000-2012): Head Gasket Failure

  • Problem: External coolant leaks, potential internal mixing
  • Mileage: 100,000-150,000 miles typical
  • Solution: Head gasket replacement with updated gaskets
  • When buying used: Verify head gaskets have been replaced or buy low-mileage (under 80,000)

FB25 2.5L (2013-2015): Oil Consumption

  • Problem: Excessive oil burning (1+ quart per 1,000 miles)
  • Cause: Piston ring design issue
  • Solution: Subaru extended warranty, engine replacement often necessary
  • When buying used: Prefer 2016+ engines or verify oil consumption is normal

EJ255/EJ257 Turbo (WRX/STI): Ringland Failure

  • Problem: Piston ringland cracks, causing compression loss and misfires
  • Cause: Detonation, aggressive tuning, high boost
  • Solution: Engine rebuild or replacement
  • When buying used: Avoid modified engines, verify stock tune and maintenance history

EZ36 3.6L: Minimal Issues

  • Most reliable Subaru engine
  • No head gasket problems
  • Excellent choice for Outback/Legacy

What to Look for in a Used Subaru Engine

When buying a replacement engine for your Subaru:

1. VIN Matching is Essential

Subaru engines vary by:

  • Year and generation
  • AWD system type (symmetrical AWD, VTD, DCCD)
  • Transmission type (manual, automatic, CVT)
  • Emissions type (federal vs California vs PZEV)
  • Turbo vs naturally aspirated

VIN matching ensures perfect compatibility.

2. Mileage Recommendations

  • EJ25 (2000-2012): Under 80,000 miles OR head gaskets already replaced
  • FB25 (2013+): Under 100,000 miles, prefer 2016+ (oil consumption fix)
  • EZ36 3.6L: Under 120,000 miles (very reliable)
  • Turbo engines (WRX/STI): Under 80,000 miles, avoid modified engines

3. Head Gasket Status (EJ25 Engines)

Ask specifically:

  • Have head gaskets been replaced?
  • If yes, what mileage and what type of gaskets used?
  • Any history of overheating or coolant loss?

4. Modification History (Turbo Engines)

For WRX/STI engines:

  • Has engine been modified or tuned?
  • Stock turbo or upgraded?
  • Maintenance history available?
  • Any track use or racing?

Avoid heavily modified engines—they're ticking time bombs.

5. Compression Testing

Demand compression test results:

  • All cylinders within 10% of each other
  • Readings within Subaru specifications
  • No signs of ringland failure or head gasket issues

6. Warranty Coverage

Protect your investment:

  • Minimum 1-year warranty
  • Preferably 2-3 years
  • Clear coverage terms in writing

Cost Comparison: New vs Used Subaru Engines

Example: 2010 Subaru Outback with 2.5L EJ25 head gasket failure

Head Gasket Repair (Not Replacement):

  • Head gasket replacement: $1,800
  • Timing belt: $600
  • Water pump: $300
  • Labor: Included above
  • Total: $2,700
  • Risk: Other engine issues may exist at high mileage

New Engine from Subaru Dealer:

  • Engine: $5,500-$7,500
  • Installation: $1,500-$2,000
  • Total: $7,000-$9,500
  • Warranty: 3 years/36,000 miles

Rebuilt/Remanufactured Engine:

  • Engine: $3,200-$4,500
  • Core charge: $500-$700
  • Installation: $1,500-$2,000
  • Total: $5,200-$7,200 ($4,700-$6,500 after core return)
  • Warranty: 1-2 years

Quality Used Engine (Used Engines Store):

  • Engine (70,000 miles, head gaskets done): $2,200-$3,200
  • Installation: $1,500-$2,000
  • Total: $3,700-$5,200
  • Warranty: Up to 3 years
  • Savings: $3,300-$4,300 vs new

For an Outback worth $8,000-$14,000, the used engine with replaced head gaskets offers excellent value.

Installation Considerations for Subaru Engines

What to replace during Subaru engine installation:

All Subaru Engines:

  • Oil and filter (use Subaru-spec 0W-20 or 5W-30)
  • Coolant (Subaru blue coolant)
  • Thermostat
  • All gaskets and seals
  • Spark plugs

EJ Engines (Timing Belt):

  • Timing belt and tensioner
  • Water pump (driven by timing belt)
  • Idler pulleys
  • Cam and crank seals

FB Engines (Timing Chain):

  • Timing chain tensioner (if noisy)
  • Water pump
  • Front main seal

Turbo Engines:

  • Turbo oil feed and return lines
  • Turbo coolant lines
  • Intercooler inspection

Total parts investment: $400-$1,200 depending on engine type

How Long Does Subaru Engine Replacement Take?

Typical labor time:

  • Outback/Legacy 4-cylinder: 12-16 hours (3-4 days)
  • Outback/Legacy 6-cylinder: 14-18 hours (3-4 days)
  • Forester 4-cylinder: 12-16 hours (3-4 days)
  • Impreza/WRX: 10-14 hours (2-3 days)

Shop timeline: 3-4 days including diagnosis, parts, and installation

Pro tip: Use a shop experienced with Subarus. Boxer engines require specialized knowledge and AWD system understanding.

Why Choose Used Engines Store for Your Subaru?

We specialize in Subaru engines:

  • All Subaru engines available - Outback, Forester, Impreza, WRX, Legacy
  • VIN matching - Perfect compatibility for your specific Subaru
  • Low-mileage inventory - Most engines under 100,000 miles
  • Compression tested - Every engine verified before shipping
  • Head gasket status disclosed - We tell you if head gaskets have been replaced
  • Up to 3-year warranties - Real protection you can trust
  • Nationwide shipping - Fast delivery anywhere in the USA
  • Expert Subaru knowledge - We understand boxer engines and AWD systems

Get Your Subaru Engine Quote Today

Ready to restore your Subaru's legendary AWD capability?

What we need from you:

  • Your Subaru's VIN (17 characters)
  • Year, model, and trim level
  • Current engine type (if known)
  • Current mileage
  • Brief description of the problem
  • Head gasket history (if applicable)

What you'll receive:

  • VIN-matched engine quote within 24 hours
  • Engine specifications and mileage
  • Head gasket status (if EJ25)
  • Warranty details (up to 3 years)
  • Shipping cost and timeline
  • Installation recommendations

Contact us today:
Email: support@usedenginesstore.com
Address: 30 N Gould St Ste R, Sheridan, WY 82801 USA

Get your Subaru running like new again with a quality, tested engine that delivers the unique boxer performance and AWD capability Subaru is famous for. Your Subaru deserves nothing less than the best replacement engine—let us help you find it.

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