Timing belt
$50 - $120 partAlready removed during the head gasket job. Replace it for almost free in labor terms.
Vehicle-specific · SubaruBay 03 · Job 04
Subaru head gasket cost: the EJ engine problem
The 2.5-litre EJ251 and EJ253 engines are the most-failed head gaskets in the modern car industry. Here is why, what each Subaru model actually costs, and what to fix while it is all apart.
Known defect
Why Subaru head gaskets fail
GASKET MATERIAL
Subaru used a graphite-based gasket on EJ251 and EJ253 engines that degraded over time, especially on the exhaust side where temperatures are highest. The gasket material literally crumbled, leaving gaps. Owners typically saw failure between 80,000 and 150,000 miles.
BOXER LAYOUT
A horizontally-opposed (boxer) engine has the cylinders pointing sideways. Coolant pools differently than in an inline or V engine, and the head gaskets sit at an angle that increases stress on the lower edge.
AFFECTED YEARS
Roughly 1996 to 2009 across most models. Subaru issued a class-action settlement in some markets and an extended warranty for others. The newer FB engines (2012+) addressed the design with multi-layer steel gaskets and largely solved the problem.
TWO TYPES OF FAILURE
External (oil seeping down the side of the engine) is more common on EJ25 and easier to live with. Internal (combustion gases into coolant, or coolant into oil) is more severe and matches classic blown-gasket symptoms.
Cost by Subaru model
What you should expect to pay
| Model | Specialist cost |
|---|---|
Forester 1998 - 2010 EJ251 / EJ253 Most affected. Specialist shops do these weekly. | $1,800 - $2,800 |
Outback 2000 - 2009 EJ251 / EJ253 Same engine family. Identical cost and procedure. | $1,800 - $2,800 |
Impreza 1999 - 2011 EJ251 / EJ253 Slightly easier engine bay than Outback. | $1,500 - $2,500 |
Legacy 2000 - 2009 EJ251 / EJ253 / EJ255 (turbo) Turbo variants cost more due to additional components. | $1,800 - $3,200 |
Baja 2003 - 2006 EJ251 / EJ253 Same engine, similar bay. Few of these on the road now. | $1,800 - $2,600 |
Tribeca 2006 - 2014 EZ30 / EZ36 Six-cylinder, much rarer failure but expensive when it happens. | $2,800 - $4,200 |
Add 30 to 40% for a Subaru dealership. Subtract 5 to 10% if a Subaru-specialist independent shop in your area does these every week.
Where to take it
Subaru specialist beats general mechanic
Counter-intuitively, a Subaru specialist often charges less than a general mechanic for this job. They have done it hundreds of times, they know which bolts always strip, they have the boxer-specific tools on the shelf, and the job takes them 8 hours instead of 14.
A general mechanic seeing their first or second EJ engine will charge for every hour they spend figuring it out. Get at least one quote from a Subaru-only or Subaru-heavy shop, even if it is across town.
How to find a Subaru specialist
- -Search NASIOC and Subaru Outback forums for shop recommendations in your area
- -Ask the parts counter at your local Subaru dealer who they recommend for out-of-warranty work
- -Look for shops that specifically advertise EJ head gasket service (very common in the US Pacific Northwest, Northeast, and mountain west)
- -Ask about their typical labor hours for the job. A specialist quotes 8 to 10. A general shop quotes 12 to 16.
Bundle it
Replace these while it's apart
Adding these parts costs $200 to $500 above the gasket job and saves $500 to $1,200 in future labor when these inevitably need replacing on a high-mileage Subaru.
Water pump
$50 - $100 partLives behind the timing belt. Same access. Replace as a matter of course.
Thermostat
$15 - $40 partCheap insurance. Old thermostats stick and cause overheating, the very thing that kills gaskets.
Valve cover gaskets
$30 - $80 partBoxer engines lean their valve covers sideways. Old gaskets seep oil. Replace while exposed.
Front main seal
$20 - $50 partBehind the timing belt. Easy to do now, $400+ later if it leaks.
Spark plugs
$15 - $40 partHard to access on boxer engines. Now is the time.
Common question
Replace both head gaskets, even if only one failed?
Usually yes. Both gaskets are the same age, same material, exposed to the same heat cycles. If one has failed, the other is on the same trajectory. The labor to do the second side is about half the first because the engine is already partly disassembled.
Expect the quote for both to be roughly 1.5x the price of one side. Some specialists quote both as the default and only do one if you insist. Their reasoning is sound: coming back six months later for the other side costs you another $1,000 in repeat labor.
Good news
Newer Subarus largely fixed the problem
The FB-series engines (FB20, FB25) introduced from 2012 use multi-layer steel gaskets and revised cooling. Failure rates are roughly the same as the industry average for inline engines.
If you own a 2012 or newer Subaru with the FB engine, do not preemptively expect head gasket failure. The known defect was specific to the older EJ251 / EJ253 design.