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Subaru Forester: EJ20 Head Gasket Failure (Single-Layer MLS)

EJ20 Head Gasket Failure (Single-Layer MLS) is a very common engine fault on the Subaru Forester on the 1997–2002 cars, and we rate it critical. Putting it right costs $1,800 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
EJ20
Years
1997–2002
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

A removed multi-layer steel head gasket held up, showing staining around the cylinder bore.Example of the part — not this vehicle

A used multi-layer head gasket. Discolouration between a cylinder and a water gallery is the tell.

John Furman · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

The Phase 1 EJ20 fitted to SF Foresters uses a single-layer metal head gasket prone to coolant and combustion gas leakage, particularly at cylinders 2 and 3. Failure typically develops slowly, causing coolant loss, white exhaust smoke and overheating. Overheating accelerates head warp, turning a gasket job into a full head resurfacing or replacement. Extremely well documented across NZ and Australian Subaru owner communities and independent workshops.

What you would notice

  • Coolant loss with no visible external leak
  • White or sweet-smelling exhaust smoke, especially on warm-up
  • Milky residue on oil filler cap
  • Overheating or temperature gauge creeping high
  • Bubbling in coolant reservoir when engine is running

How to check it

Where to look. Cylinder head-to-block mating surfaces, EJ20 flat-four engine

Pressure-test cooling system; check oil filler cap for white emulsion; inspect exhaust for white smoke on start-up; use combustion block tester on coolant reservoir; ask owner about coolant top-up frequency.

Parts involved: Head gasket.

What it costs to put right

$1,800 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

  • “Has the head gasket ever been replaced?”
  • “Has the engine ever overheated?”
  • “How often has the coolant needed topping up?”
  • “Has a combustion leak test been done recently?”

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 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.

Subaru Forester buyer questions

Is ej20 head gasket failure (single-layer mls) serious on a Subaru Forester?

We rate it critical and very common on the Subaru Forester. The Phase 1 EJ20 fitted to SF Foresters uses a single-layer metal head gasket prone to coolant and combustion gas leakage, particularly at cylinders 2 and 3. Failure typically develops slowly, causing coolant loss, white exhaust smoke and overheating. Overheating accelerates head warp, turning a gasket job into a full head resurfacing or replacement. Extremely well documented across NZ and Australian Subaru owner communities and independent workshops.

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

$1,800 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 1997–2002 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.

How do I check for it before I buy?

Pressure-test cooling system; check oil filler cap for white emulsion; inspect exhaust for white smoke on start-up; use combustion block tester on coolant reservoir; ask owner about coolant top-up frequency. Look here: Cylinder head-to-block mating surfaces, EJ20 flat-four engine