Subaru Impreza: EJ25 Phase 2 head gasket external coolant/oil seep

The EJ257/EJ251/EJ253 Phase 2 head gasket is a multi-layer steel design prone to external seeping at the cylinder head-to-block deck face, particularly on the front exhaust side near coolant galleries. Seeping typically starts between 80,000 and 150,000 km and progresses from a minor weep to active external leakage. If left unaddressed, coolant loss can lead to localised overheating and catastrophic engine damage. Both cylinder banks can be affected simultaneously and the head deck surface may require resurfacing.

• Sweet smell from engine bay after heat soak
• Visible coolant staining or residue at cylinder head and block deck seam
• Oil staining at head gasket join line on one or both banks
• Coolant level dropping slowly over weeks without visible ground puddle
• White crusty deposits or rust streaking around head gasket seam

1. 1

   With engine warm, inspect the cylinder head-to-block seam on both sides of the flat-four engine for coolant staining, oil seeping, or discolouration.

2. 2

   Check coolant reservoir level trend across multiple drives.

3. 3

   Inspect radiator cap underside for oily film indicating internal mixing.

Parts involved: Head gasket.

$1,800 to $3,800 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the head gasket been replaced, and if so by whom and at what mileage?”
• “Has the car ever overheated or required unexpected coolant top-ups?”
• “Can you provide workshop invoices for any cooling system work?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.