Subaru Legacy: EJ251/EJ254 2.5 external head gasket coolant leak (BE/BH)
EJ251/EJ254 2.5 external head gasket coolant leak (BE/BH) is a very common cooling fault on the Subaru Legacy on the 1999–2003 cars, and we rate it major. Putting it right costs $2,200 to $4,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 54 documented faults on the Subaru Legacy.
- Vehicle
- Subaru Legacy
- Engine
- EJ251 / EJ254
- Years
- 1999–2003
- Fuel
- petrol
- System
- Cooling
What you are looking at
Example of the part — not this vehicleA used multi-layer head gasket. Discolouration between a cylinder and a water gallery is the tell.
What goes wrong
The Phase 2 2.5 boxer in the BE/BH Liberty and Legacy is one of the most documented head gasket failers Subaru ever built: the composite gaskets weep coolant (and often oil) externally, usually starting on the side of the engine nearest the battery. Subaru ran service campaign WWP-99 in the US for 1999-2002 2.5 cars, adding cooling system conditioner and extending head gasket warranty - an admission of how widespread it is; that warranty is decades expired. A slow external weep can run for months, but ignored it ends in coolant loss and an overheated, warped engine. On a car this age assume the gaskets have either been done or will need doing.
What you would notice
- Coolant level slowly dropping with no puddle on the ground
- Sweet coolant smell after a drive
- Crusty green or white residue along the join between head and block
- Oil weep low on the engine sides
- Temperature gauge creeping up on hills in bad cases
How to check it
Where to look. Head-to-block join on both sides of the flat-four engine, most often the side nearest the battery
With the engine warm after the test drive, sniff around the engine bay for a sweet coolant smell. Use a phone torch to look along the join between each cylinder head and the block from above - the side nearest the battery fails most often - for green/white crusty residue or fresh wet coolant. Check the coolant reservoir level and ask when it was last topped up. Ask directly whether the head gaskets have ever been replaced and look for the invoice; a receipted head gasket job with machined heads is a strong point in the car's favour. If a workshop inspection is possible: have the cooling system pressure-tested and the sniff test done for combustion gases, and get the underside checked for gasket weep with the car raised.
What it costs to put right
$2,200 to $4,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Have the head gaskets been replaced, and is there an invoice?”
- “Does it ever lose coolant between services?”
- “Has the car ever overheated?”
Now check the Subaru Legacy you are actually looking at
Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.
Where this comes from
- Subaru Service Campaign WWP-99 - cooling system conditioner for 1999-2002 2.5L external head gasket leaks
- All Wheel Drive Auto - 'Subaru Head Gaskets Problems Explained Part II' (Phase 2 2.5 external leak pattern)
- NASIOC thread 'WWP-99 Service Campaign - Cooling System Conditioner'
- MotorSift NZ - 'Used Subaru Outback & Legacy Buyer Guide' (EJ head gaskets)
Subaru Legacy buyer questions
Is ej251/ej254 2.5 external head gasket coolant leak (be/bh) serious on a Subaru Legacy?
We rate it major and very common on the Subaru Legacy. The Phase 2 2.5 boxer in the BE/BH Liberty and Legacy is one of the most documented head gasket failers Subaru ever built: the composite gaskets weep coolant (and often oil) externally, usually starting on the side of the engine nearest the battery. Subaru ran service campaign WWP-99 in the US for 1999-2002 2.5 cars, adding cooling system conditioner and extending head gasket warranty - an admission of how widespread it is; that warranty is decades expired. A slow external weep can run for months, but ignored it ends in coolant loss and an overheated, warped engine. On a car this age assume the gaskets have either been done or will need doing.
How much does it cost to fix on a Subaru Legacy?
$2,200 to $4,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.
Which Subaru Legacy years are affected?
Our research records this fault on the 1999–2003 Subaru Legacy. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.
How do I check for it before I buy?
With the engine warm after the test drive, sniff around the engine bay for a sweet coolant smell. Use a phone torch to look along the join between each cylinder head and the block from above - the side nearest the battery fails most often - for green/white crusty residue or fresh wet coolant. Check the coolant reservoir level and ask when it was last topped up. Ask directly whether the head gaskets have ever been replaced and look for the invoice; a receipted head gasket job with machined heads is a strong point in the car's favour. If a workshop inspection is possible: have the cooling system pressure-tested and the sniff test done for combustion gases, and get the underside checked for gasket weep with the car raised. Look here: Head-to-block join on both sides of the flat-four engine, most often the side nearest the battery