Subaru 2004-2006 STI Head Gaskets (Build Dates 1/04-6/06) 11044AA642
The OEM Subaru EJ255 2.5L 06-07 WRX & EJ257 04-06 2.5L STI head gasket is multi-layered steel. The OEM EJ25 gaskets have been shown to hold up under extensive boost pressures and high temperatures. Subaru 2.5L engines built on 06/2006 and before require a different part number then 2.5L engines built on 07/2006 and after.
- 04-06 STI stock head gaskets are .6mm (.023 in) thick.
- Please refer to your drivers side door jam to determine the build date of your vehicle.