2009 Subaru Outback Problems: 1 Issues Every Owner Should Know
2009 model year · 4,521+ owner reports · Updated April 2026
According to Au7o's analysis of 4,521+ owner reports, the 2009 Subaru Outback has 1 documented known issues, with 1 rated critical. The most serious is Head Gasket Failure ($1,500-$2,500 repair). The most commonly reported issue is Head Gasket Failure with 4,521 owner reports. Across all issues, repair costs range from $1,500 to $2,500. DIY maintenance guides at au7o.io.
All 1 Known Issues
On the 1999-2010 Subaru Outback 2.5L H4, the 2.5L non-turbo engine is known for external head gasket leaks. Oil seeps past the gasket and can contaminate the coolant. Subaru extended warranties and improved gasket design in later years.
Common Symptoms
- Oil leaking externally from engine
- Coolant mixing with oil (milky appearance)
- Overheating
- Sweet smell from engine bay
- Bubbles in coolant reservoir
How to Fix
Replace head gaskets with updated MLS (multi-layer steel) gaskets. Ensure the machine shop resurfaces cylinder heads to proper flatness. Replace timing belt, water pump, and thermostat while engine is apart. Use Subaru coolant conditioner to help prevent future failures. Budget $1,500-2,500 for a quality repair.
What Owners Are Using
Parts and tips from 4,521+ owners who fixed this issue
- TipDIY repairs can save significantly - dealer charges $1,500-2,500 but DIY costs are typically 50-70% less
- TipUse Subaru coolant conditioner to help prevent future failures.
- NoteThis is a high-severity issue - ignoring it can lead to costly repairs or safety concerns. Address it promptly.
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
- UpgradeComplete timing belt kit with water pump for a comprehensive replacement (Gates Timing Belt Kit with Water Pump)
- UpgradeHigh-quality engine oil is critical after timing service (Castrol Edge Full Synthetic Motor Oil)