2006–2009 Subaru Legacy: Head gasket leak (2.5L EJ25 coolant or oil seep)
Likely causes, ranked
- External head gasket seep (both gaskets replaced with MLS type, heads resurfaced)$1,800–$3,500Shop
- Internal failure after overheating (coolant in oil or exhaust)Shop
- Slow seep managed temporarily with Subaru coolant conditionerDIY
Real-owner fix counts will appear here as reports come in.
Rough cost: $1,800–$3,500DIY or shop: See DIY or shop section
Parts to check
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Symptom: Sweet coolant smell, slowly dropping coolant level, crusty residue or drips low on the engine near where the heads meet the block, and sometimes overheating on hills or in summer traffic.
Likely causes
- External seep at the head-to-block seam. The naturally aspirated EJ25 is known for weeping coolant or oil externally, typically between roughly 60,000 and 150,000 miles. Owners and independent shops recommend replacing both gaskets with multi-layer-steel (MLS) gaskets and having the heads checked and resurfaced.
- Internal failure. Less common. Look for milky oil, white exhaust smoke, or coolant loss with no visible leak. It costs more, especially if a head is warped.
- Stopgap. Subaru Outback Forums owners mention the inexpensive Subaru coolant conditioner for slow external seeps. It buys time and doesn't repair the gasket.
Rough cost range
| Repair | Reported |
|---|---|
| Both head gaskets, independent shop | About $1,800–$3,500 (often bundled with timing belt, water pump and seals) |
DIY or shop?
Shop for most owners. It's a long job, often done with the engine out. Ask the shop to resurface the heads and use MLS gaskets.
Useful steps
- Check the coolant level weekly and look for residue under the engine.
- Don't keep driving if the temperature gauge climbs.
- Ask for the timing belt, water pump and seals while it's apart.
- Compare an independent Subaru specialist with the dealer quote.
Vehicle focus: 2006–2009 Subaru Legacy.
Safety / mechanic note
Overheating can quickly turn a seep into a ruined engine. Verify with a mechanic before long trips.
Recalls & service bulletins
No recalls or service bulletins are listed for this page yet.
NHTSA complaints: 7 keyword-matched complaints (of 249 unique complaints filed under NHTSA model names LEGACY, 2006–2009; NHTSA complaints API by model year, queried 2026-10-15).
Always check your VIN for open recalls at nhtsa.gov/recalls.
Sources
What actually fixed it?
Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.