What goes wrong
The multi-layer steel (MLS) head gaskets can degrade and fail, leading to external oil or coolant leaks. In more severe cases, exhaust gases can enter the cooling system, causing overheating, or coolant can enter the combustion chamber, leading to misfires.
Symptoms to watch for
- External oil leaks from cylinder heads
- External coolant leaks from cylinder heads
- White smoke from exhaust
- Overheating
- Misfires (P0301, P0302, P0303, P0304)
- Coolant consumption with no visible leaks
- Sweet smell from exhaust
Root cause
The original equipment head gaskets (part number 11044AA483 / 11044AA642 on EJ253 engines) are prone to failure due to their design, which can degrade over time, especially with age and mileage.
Buy time with these
- • Regular coolant flushes (every 30k miles) using Subaru Super Coolant
- • Promptly address any signs of coolant or oil leaks
- • Avoid engine overheating as much as possible
Permanent fix
- Replace head gaskets with updated multi-layer steel (MLS) gaskets (e.g., Fel-Pro 26415PT or Ishino 11044AA770)
- Machine cylinder heads for flatness and inspect for cracks
- Replace head bolts
- Perform timing belt and water pump service simultaneously
FAQ
What causes head gasket failure?
The original equipment head gaskets (part number 11044AA483 / 11044AA642 on EJ253 engines) are prone to failure due to their design, which can degrade over time, especially with age and mileage.
How much does it cost to fix?
National average $1,800–$2,800.
Is this a DIY repair?
Difficulty 4/5. Replace head gaskets with updated multi-layer steel (MLS) gaskets (e.g., Fel-Pro 26415PT or Ishino 11044AA770)
What are the symptoms?
External oil leaks from cylinder heads; External coolant leaks from cylinder heads; White smoke from exhaust; Overheating; Misfires (P0301, P0302, P0303, P0304); Coolant consumption with no visible leaks; Sweet smell from exhaust