Subaru losing coolant or running hot?
Could be the head gaskets. Better Call Fares.

Tell me your year, model and mileage and what it's doing with the coolant. I'll tell you straight if it's the classic boxer head-gasket leak — and flat-quote the proper fix at your driveway.

⚡ Reply within 1 hour 📍 At your driveway 🔧 Proper boxer head-gasket job

Prefer to talk? Call or text 647-450-0406 — answered 24/7.

Booking Subaru HG jobs

Get a flat quote

Takes 30 seconds. I'll text you back with diagnosis + a real number.

No spam. Reply usually under 1 hour. Or call 647-450-0406.

Subaru · Head Gasket

Subaru Head Gasket Leak? What the Repair Really Costs (GTA)

Written by Fares · Mobile mechanic, Mississauga & the GTA · Updated June 2026 · 7 min read

A Subaru that's slowly losing coolant, running warm, or giving off a sweet smell is very often the classic boxer-engine head-gasket leak (the EJ25 in the Outback, Forester, Legacy and Impreza). The horizontally-opposed layout puts the head gaskets on the sides of the engine, where they tend to weep coolant externally as the car ages. The proper fix replaces both head gaskets with the updated parts while the engine's apart. Dealers quote $2,500–$3,500+; Cars With Fares does it for a flat quote first. Call or text 647-450-0406.

Your Outback, Forester, Legacy or Impreza keeps needing coolant but there's no puddle on the driveway, maybe it runs a touch warm, and there's a faint sweet smell after a drive. The dealer said "head gaskets" and a number north of three grand. If it's an older boxer Subaru, they're very likely right — this is one of the most well-known issues on these cars. Here's the real picture.

I'm Fares, a mobile mechanic in Mississauga. The Subaru head gasket is a job I know well, and it's a different animal from most cars because of how Subaru builds their engines.

What's actually failing

Subaru uses a horizontally-opposed "boxer" engine — the cylinders lie flat and point out to the sides instead of standing up in a V or a line. That's great for balance and a low centre of gravity, but it means the head gaskets sit on the sides of the engine, and on the older EJ25 (roughly the naturally-aspirated 2.5L in 2000s–early 2010s Outbacks, Foresters, Legacys and Imprezas) those gaskets are prone to failing.

On these, the failure is usually an external coolant leak — the gasket weeps coolant out the side of the engine where it evaporates off the hot block, which is why you lose coolant with no visible puddle and get the sweet smell. Less often it leaks internally (combustion gases into the coolant, or coolant into the oil — milky residue under the cap). Either way it's a head-gasket job. Subaru released updated gasket material over the years, and the proper repair uses the improved parts so it doesn't just fail again.

How to confirm it

I confirm it properly: pressure-test the cooling system to find the weep, and on a suspected internal leak, a combustion-gas (block) test on the coolant tells us if exhaust gases are getting in. I want to be sure it's the gaskets and not a simpler leak (a hose, the water pump, a thermostat housing) before quoting a big job.

An honest caveat on older Subarus: a head-gasket job is a real expense, so on a very high-mileage car I'll be straight about whether it's worth it versus the car's value. That said, a well-kept Outback or Forester is often worth saving — they go a long way once the gaskets are done right. I'll give you the honest call for your specific car.

What the real fix involves

This is a labour-heavy job because the engine has to come apart at the heads. The proper repair: both head gaskets replaced with the updated parts (always in pairs on a boxer — never just one side), the heads checked/cleaned and resurfaced if needed, and while it's all apart, it's the smart time to do the timing belt, water pump and the related seals if they're due, because the labour overlaps massively. Doing those together saves you a second teardown later.

The honest GTA cost

Straight numbers. The exact figure depends on your engine and whether we bundle the timing/pump work, but here's the honest GTA range.

The flat quote

Dealer/shop: typically $2,500–$3,500+

At your place with Cars With Fares: usually $1,800–$2,600 for both head gaskets done with updated parts, flat-quoted before any work.

That's both gaskets, resurfacing as needed, and labour as one number. It goes up if we bundle in the timing belt, water pump and seals — which is usually the smart move on an older boxer since the engine's already open.

It lands under the dealer because there's no shop overhead stacked on, not because anything's skipped — both sides, updated gaskets, done once. The savings is the byproduct; you're paying for the job done properly so the leak's actually gone.

Why mobile works here — and why trust matters

This is a bigger job, but it's one I do at your place with proper support, so you're not handing the car to a shop for several days. On a repair this size you want to trust the person doing it — you can see the old gaskets come out, see the updated parts go in, and you got a flat quote up front that doesn't grow into a "while we were in there" surprise. And bundling the timing belt and pump while it's apart is exactly the kind of honest call you want from someone who's standing in front of you, not a service writer upselling from a desk.

Can you keep driving it?

A slow external coolant leak isn't an instant emergency — but the danger is running low on coolant and overheating, and an overheated boxer can warp the heads and turn a gasket job into a much bigger one. So the rule is: keep a close eye on the coolant level, and if it ever runs hot or the temp gauge climbs, stop and let it cool — don't push on. If it's an internal leak (milky oil, bubbling overflow, white smoke), get it looked at sooner. Either way, get it on the books before a hot summer day or a cold snap forces the issue.

Get a real diagnosis and a flat quote

Tell me your year, model, mileage and what's happening with the coolant — I'll tell you if it's the boxer head gaskets and quote the proper fix at your driveway.

Get My Quote →

FAQ

How much does a Subaru head gasket job cost in the GTA?

Replacing both head gaskets on a boxer Subaru with updated parts runs roughly $1,800–$2,600 done at your home, versus $2,500–$3,500+ at a dealer or shop. The number goes up if you bundle the timing belt, water pump and seals while the engine's apart, which is usually the smart move on an older boxer since the labour overlaps. I flat-quote it before any work and confirm it really is the gaskets first with a pressure and combustion-gas test.

Which Subarus have the head gasket problem?

It's mainly the older naturally-aspirated EJ25 2.5L boxer in the Outback, Forester, Legacy and Impreza, roughly through the 2000s and into the early 2010s, usually showing up past 150,000 km. The classic version is an external coolant leak (losing coolant with no puddle, sweet smell, crusty residue on the side of the engine). Newer Subarus are much less prone to it. The fix uses updated gasket material so it doesn't just repeat.

Should I do the timing belt at the same time as the head gaskets?

On an older boxer Subaru, almost always yes. The engine has to come apart at the front to do the head gaskets anyway, and that's most of the labour for a timing belt, water pump and seals too. Doing them together means you're not paying for that teardown twice. If your timing belt and pump are anywhere near due, bundling them in is the smart, cheaper-over-time move — I'll lay out the math for your specific car.

Can you replace Subaru head gaskets at my house?

Yes — with proper support it's a driveway job across Mississauga and the GTA, and you get to watch the old gaskets come out and the updated parts go in instead of leaving the car at a shop for days. I always do both sides (never just one on a boxer), check and resurface the heads as needed, and flag the timing belt and water pump while it's apart. You get a flat quote up front and it's the number you pay.

Subaru losing coolant? Cooling system repair · Engine repair · is your shop quote fair? · get a flat quote

Subaru losing coolant or running hot? Better Call Fares.

I confirm the boxer head-gasket leak and do the proper both-sides job with updated parts at your driveway across the GTA. Flat quote before any work starts.

Call 647-450-0406