Subaru Head Gasket Warning Signs Denton TX Owners Should Know, from Pierce Family Automotive

A failing Subaru head gasket usually shows up three ways: coolant that keeps disappearing, white smoke from the tailpipe, and an engine that runs hotter than it should. If your Outback, Forester, Legacy, or Impreza was built between 1996 and 2011, it has the 2.5 liter EJ engine, and head gasket failure on that engine is not a maybe. It's a mileage question.

The head gasket seals the cylinder head to the engine block, keeping combustion pressure in and oil and coolant in their own passages. When it fails, those fluids leak or mix, and the engine pays for it.

We see this repair all the time at Pierce Family Automotive on Fort Worth Drive in Denton, and July is peak season for it. A gasket that seeped quietly all spring tends to let go the first week the thermometer hits 100.

This is usually the first clue, and the easiest one to shrug off. If you're topping off the overflow tank more than about once a month and the rest of the cooling system checks out, the head gasket moves to the top of the suspect list.

On EJ engines the leak usually starts on the outside, right at the seam where the head meets the block. You might spot a wet, oily line low on the engine, a few drops on the driveway, or catch a sweet, almost maple-syrup smell after you park. Often there's no puddle at all, the coolant burns off the hot exhaust before it reaches the ground.

Thin white vapor on a cool morning is condensation. It clears in a minute or two. White smoke that keeps coming after the engine is fully warm is a different animal. That's coolant getting into a cylinder and burning, which means the gasket has failed internally.

Two more clues usually ride along with it: bubbles rising in the coolant overflow tank while the engine idles, and a milky film under the oil filler cap where coolant has mixed into the oil. An internal leak is the serious version of this problem. Don't sit on it.

Early on, the temperature gauge might only climb in stop-and-go traffic, then settle back down once you're moving. Plenty of Denton drivers first notice it crawling up I-35E at 5 pm, or sitting through the lights on University Drive. A leaking gasket lets the cooling system lose pressure and pull in combustion gas, which creates air pockets that block coolant flow.

An engine that overheats once can survive. An engine that overheats a dozen times usually doesn't.

Why do EJ Subaru engines have head gasket problems?

Blame the layout and the gasket material together. Subaru's boxer engine lays its cylinders flat, so the two heads sit low on the sides of the block, soaking in oil and coolant even when the car is parked. On the non-turbo 2.5 liter EJ25, Subaru paired that layout with a single-layer composite gasket whose coating breaks down over years of heat cycles.

Most failures land between 100,000 and 150,000 miles, sooner if the cooling system was neglected. The lasting fix is the one Subaru eventually adopted itself: multi-layer steel gaskets, plus resurfaced heads and a fresh timing belt and water pump while the engine is apart, since the labor overlaps almost completely.

When to bring your Subaru in

Sooner is cheaper. An external seep caught early gives you time to plan the repair around your schedule. A full overheat can crack a head and add four figures to the bill. Bring the car in if any of these sound familiar:

We confirm the diagnosis before anyone talks money. A cooling system pressure test and a combustion gas test tell us whether it's really the head gasket or something cheaper, like a bad radiator cap or a stuck thermostat. You'd be surprised how often a $400 fix gets misdiagnosed as a $2,500 one.

On price, straight talk: across the industry, EJ head gasket jobs at independent shops generally run $1,800 to $2,500, more if the heads need machine work or the engine overheated badly. It's a big job, and it belongs at a shop that does it regularly. Our Subaru repair and service program exists because Denton has a lot of these cars on the road, and our engine repair work is backed by a 3 year, 36,000 mile warranty. Financing is available, and after-hours drop off means you can leave the car whenever works.

One more thing while you're at it: punch your VIN into NHTSA's recall lookup. It occasionally turns up an open recall a previous owner never handled. And if your gasket hasn't failed yet, the Car Care Council has solid guidance on cooling system upkeep, the best way to stretch its life.

Common questions