Procedure
- Pull the engine. You can fight an EJ head job in the car on jack stands, but the engine comes out of a Subaru in under two hours and you will save that time ten times over on reassembly.
- With the engine on a stand, remove intake, exhaust, timing components, cam carriers, and heads. Bag and label every fastener by subassembly — EJ bolt lengths are unforgiving.
- Check both the block deck and head surfaces with a straightedge and feeler gauge. Anything beyond 0.05mm warp on the heads goes to a machine shop for resurfacing.
- Clean deck surfaces to bare metal with plastic scrapers and solvent only — never a grinding disc on an aluminum EJ deck. Debris in a cylinder or oil gallery will end the engine.
- Fit MLS (multi-layer steel) gaskets dry — no sealant, no spray copper. Verify the gasket orientation marks; EJ gaskets install one way only.
- Torque the 12-point head bolts in the factory multi-stage sequence: initial torque, loosen sequence, re-torque, then the final angle stages. Follow your year FSM exactly — the sequence differs across EJ generations.
- Reassemble with a new timing belt, tensioner, idlers, and water pump while everything is apart. Nobody wants back in here at 105k.
- Refill with coolant using Subaru conditioner, burp the system nose-up, and hold the engine at idle through two full fan cycles while watching for bubbles in the overflow.
Work at your own risk. Torque values and procedures vary by vehicle — always confirm against the factory service manual for your exact model.