MajorVery commonEngine

Subaru Forester: EJ25 SOHC head gasket external leak (SG/SH 2.5 non-turbo)

EJ25 SOHC head gasket external leak (SG/SH 2.5 non-turbo) is a very common engine fault on the Subaru Forester on the 2002–2010 cars, and we rate it major. Putting it right costs $2,500 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 50 documented faults on the Subaru Forester.

Vehicle: Subaru Forester
Engine: EJ25
Years: 2002–2010
Fuel: petrol
System: Engine

This page covers the Subaru Forester as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Subaru Forester faults50 documented faults on this model

What you are looking at

What goes wrong

The classic Subaru fault. The single-overhead-cam EJ251/EJ253 2.5L in SG Foresters (and early SH until the FB engine arrived around 2011) develops external head gasket leaks, typically from about 150,000 km. It starts as a slow oil or coolant weep between the block and head, then progresses to coolant loss and overheating. If ignored the engine overheats and can warp the heads. Subaru quietly updated the gasket and dosed cooling systems with conditioner, but there was never a recall, so most NZ cars fixed it out of pocket. A proper repair means both sides done with multi-layer steel gaskets, plus timing belt and water pump while the engine is apart.

What you would notice

Sweet coolant smell after a drive
Oil weep low on the block/head join
Coolant level slowly dropping
Temperature gauge creeping on hills
Crusty green/white residue on the underside of the engine

How to check it

Where to look. Both sides of the boxer engine where the cylinder heads bolt to the block, low in the engine bay

With the engine cold, look and feel along the head-to-block seam on both sides from under the car (torch needed) for wet oil or dried coolant crust. Check the coolant overflow bottle for level and any oily film. After the test drive, sniff around the engine bay for coolant. Ask for invoices — if the gaskets were done, you want to see MLS gaskets and a machined-head note on the bill.

Parts involved: Head gasket, Turbocharger.

What it costs to put right

$2,500 to $4,500 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.

Ask the seller

“Have the head gaskets been replaced, and is there an invoice?”
“Were the heads machined and multi-layer steel gaskets used?”
“Has it ever overheated?”

Now check the Subaru Forester 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.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

All Wheel Drive Auto 'Subaru Head Gasket Problems Explained'
Ultimate Subaru Message Board head gasket threads
subaruforester.org SG head gasket threads
MechanicBase 'Subaru Head Gasket Problems: Years And Models Affected'

Subaru Forester buyer questions

Is ej25 sohc head gasket external leak (sg/sh 2.5 non-turbo) serious on a Subaru Forester?

We rate it major and very common on the Subaru Forester. The classic Subaru fault. The single-overhead-cam EJ251/EJ253 2.5L in SG Foresters (and early SH until the FB engine arrived around 2011) develops external head gasket leaks, typically from about 150,000 km. It starts as a slow oil or coolant weep between the block and head, then progresses to coolant loss and overheating. If ignored the engine overheats and can warp the heads. Subaru quietly updated the gasket and dosed cooling systems with conditioner, but there was never a recall, so most NZ cars fixed it out of pocket. A proper repair means both sides done with multi-layer steel gaskets, plus timing belt and water pump while the engine is apart.

How much does it cost to fix on a Subaru Forester?

$2,500 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 Forester years are affected?

Our research records this fault on the 2002–2010 Subaru Forester. 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.