Subaru EJ25 Head Gasket Replacement Guide
Subaru EJ25 head gasket failure is the most common and expensive repair Subaru owners face. There are two types — external oil seep (manageable) and internal coolant leak (urgent).
Call (650) 588-9199Labor Time
10-14 hours
Pricing
Quoted after inspection
Serving
San Bruno, San Francisco, San Mateo, South San Francisco, Daly City
Warranty
2 years / 24,000 miles
Common Symptoms
If you experience these symptoms, your Subaru Outback / Legacy / Forester / Impreza may need head gasket replacement:
Why This Happens
Understanding the root cause helps prevent future issues:
Our Repair Process
How we handle head gasket replacement at Express Auto in San Bruno:
Coolant system pressure test: confirm internal vs. external leak and locate source
Block test (combustion leak test): chemical test detects exhaust gases in coolant — confirms internal leak without disassembly
Cylinder leakdown test: measure seal integrity on each cylinder, identify severity
Remove cylinder heads: requires draining coolant, intake manifold removal, and careful head bolt sequence
Machine shop cylinder head resurfacing: critical — reusing a warped head causes immediate re-failure. Heads must be measured and resurfaced to spec
Replace head gaskets with revised MLS (Multi-Layer Steel) Subaru OEM gaskets
Replace all head bolts: Subaru head bolts are torque-to-yield and must never be reused
Reassemble with proper torque sequence, refill and bleed cooling system
Verify repair: pressure test, check for exhaust gases in coolant, road test to operating temperature
Parts & Warranty
Parts Used
gaskets
OEM Subaru head gaskets (revised MLS design)
headbolts
New OEM head bolts — never reuse (torque-to-yield)
machining
Cylinder head resurfacing at machine shop (both heads)
coolant
Subaru Super Coolant (SOA868V9210) — do not use generic green antifreeze
Service Details
Labor Time
10-14 hours
Pricing
Quoted after inspection
Warranty
2 years / 24,000 miles
Frequently Asked Questions
What is the difference between external seep and internal head gasket leak on a Subaru?
External seep (also called "external oil leak"): oil seeps out along the edge of the gasket and drips onto the exhaust. You will see oil spots under the car. This is the most common Subaru EJ25 failure mode and is serious but not immediately catastrophic — you have time to plan and budget for the repair. Internal coolant leak: combustion gases leak into the coolant system. You lose coolant with no visible drip, get white exhaust, and risk overheating.
How much does Subaru head gasket replacement cost?
We quote it after an inspection. The biggest cost variable is whether the cylinder heads are warped and need resurfacing — we always measure before assuming. Skipping resurfacing invites a repeat failure.
Which Subaru models and years have the EJ25 head gasket problem?
The most affected vehicles: 2000-2009 Subaru Legacy 2.5, 2000-2009 Subaru Outback 2.5, 2001-2009 Forester 2.5 (non-turbo), 2000-2011 Impreza 2.5. The SOHC (single overhead cam) EJ25 has the highest failure rate. The DOHC EJ25T turbo (WRX, Forester XT, Legacy GT) is less prone but not immune. Subaru issued Technical Service Bulletins and extended warranty coverage on some years — ask us if yours qualifies.
Can I keep driving with a Subaru head gasket leak?
With an external oil seep only: yes, for a while — monitor oil level weekly and schedule repair within 3-6 months. With an internal coolant leak: no. Coolant in the combustion chamber causes white exhaust smoke and you are slowly losing coolant. Two overheating events can crack the heads. Drive carefully and repair immediately.
Does Express Auto also repair Subaru WRX and STI head gaskets?
Yes. WRX (2002-2014 with EJ20 or EJ25T turbo) and STI (2004-2021 with EJ25 DOHC turbo) head gasket service is within our capability. Turbocharged EJ head gaskets are less common but do fail — often from overheating or deferred coolant service. STI owners: if you have been running E85 or raised boost, mention this — it affects head gasket heat cycling and our repair approach.
Need this Subaru repair?
Book online in 2 minutes — no deposit. Honest estimate before any work — we service Subaru Outback / Legacy / Forester / Impreza and other makes.