Subaru Cylinder Head Gasket Problems (Years to Avoid)
Some Subarus are known for wearing out their cylinder head gaskets with very low mileage. Where does this reputation come from? There has never been an official Subaru head gasket recall, but the problem is so widespread that certain OEM head gaskets can be expected to fail at 100,000 to 150,000 miles (160,000 to 241,000 kilometers).
That may sound like a long time, but considering most Subaru owners want their cars to last longer than 250,000 miles, that’s a pretty big deal. And the repair bills can be pretty expensive.
Affected Years and Models
Single overhead camshaft (SOHC) variants experience the error much more frequently than dual overhead camshaft (DOHC) variants. SOHC engines can be identified by a single circular notch on each side of the engine. However, DOHC engines manufactured between 1996 and 1999 have also been known to leak. The naturally aspirated EJ25 engine is used across the Subaru range and is found in non-turbo Baja, Forester, Impreza, Legacy and Outback models. Head gasket failure is less common in Subaru 3.0 and 3.6L H6 models such as the Tribeca.
Subaru Head Gasket Leak Symptoms
Black carbon deposits at the bottom of cylinder #4 (right) are a classic symptom of a leaking head gasket. Many of the symptoms of a leaking head gasket in a Subaru are very similar to a leaking head gasket in other vehicles.
1) Oil leaks
A blown head gasket can show up in a variety of ways. First-generation Outback and second-generation Legacy models have a tendency for the seal to leak to the outside. You may see an oil leak between the cylinder head and the engine block.
2) Blowing cold air out of the heater
Many Subaru cooling systems wire the heater core in such a way that air in the heater core will cause cold air to blow out of the heater. Assuming the cooling system is properly bled, air in the heater core is most often caused by a leaking head gasket. This problem is common on second generation Outbacks, as these leaks are usually internal.
3) Overheating
One of the obvious symptoms of a head gasket leak is an overheating engine. If your engine overheats, stop and let it cool a bit before continuing. An overheating engine can cause extensive engine damage and costly repairs.
4) White Exhaust Smoke
If you notice thick white smoke coming from the exhaust even after the initial start, you may have a head gasket leak. However, just because you don’t notice excessive white smoke doesn’t mean it’s tight.
5) Foamy Oil Cap
Does the bottom of your oil cap look like a black coffee or a Starbucks Frappuccino? If it’s the latter, this is a warning sign that coolant has gotten into your oil system. Coolant and oil don’t like to mix and often form a milky foam on contact.
6) Bubbles in the overflow container
There should be no air in the cooling system. If the tank overflows and bubbles form while the engine is running, it is a sure sign that something is wrong. While you are at it, check if the radiator cap is in good condition. A similar phenomenon can occur if the cap is damaged.
7) Hydrocarbons in the radiator
Hydrocarbons are produced when gases ignite in the combustion chamber. If you see these symptoms in your radiator, it may mean that combustion gases are leaking into the cooling system through the head gasket. You may smell burnt oil or fuel coming from the radiator or coolant overflow tank. If you notice this unusual smell, we recommend having your cooling system tested as soon as possible.
What is a Head Gasket?
The head gasket forms the sealing surface between the cylinder head and the block. This thin piece has a very tough job. It is necessary to keep the coolant in the water jacket, the oil in the oil passages, and the combustion gases from entering the cooling system. This task must be performed over a wide range of temperatures from cold start to normal operating temperatures.
Some head gaskets are composites made from other materials such as paper and graphite. Most modern cylinder head gaskets are made from multi-layer steel (MLS).
What causes a head gasket leak? Notice how the blue gasket material on cylinder #4 (top right) has eroded away. This could allow combustion gases to enter the cooling system. There has been much speculation as to the exact cause of Subaru’s widespread head gasket leaks.
Suspected causes include faulty head gasket material, poor engine maintenance, poor head gasket design, poor water jacket design, detonation, improperly tightened cylinder head, and electrolysis of the coolant due to poor grounding.
How do I test a cylinder head gasket? There are several ways to test the integrity of the cooling system and combustion chamber. A leak test is a sure way to see if the head gasket has a leak.
If you see bubbles coming from the radiator filler neck or overflow tank during a leak test, you have a leak in the head gasket.
A radiator pressure test will confirm that the cooling system is leak-free. This test attaches to the filler neck of your radiator and applies pressure that the system is designed to withstand. If the system cannot hold the pressure, you have a leak somewhere.
False positives can also occur if you use petroleum-based additives in your radiator. Do Subarus still have head gasket problems? So what year did Subaru fix this problem? There is no definitively “safe” model year, but head gasket leaks are common in newer models. If your Subaru is a 2012 or newer, there’s a good chance it won’t have an issue. Can I continue to drive with a blown head gasket?
The leak wasn’t too bad so the damage was minimal. I do not recommend continuing to drive with a blown head gasket. The longer the problem persists the worse it will get. Driving with a leaking head gasket will ultimately cause more damage to your engine and more expensive repairs in the long run.
In an emergency, a leaking head gasket is unlikely to prevent you from driving your vehicle, especially if the leak is minor. Keep an eye on your water temperature gauge, as extended driving can cause the engine to overheat.
An overheated engine can deform the cylinder head, making it unusable. How much does it cost to replace a cylinder head gasket? Replacing a head gasket is fairly inexpensive (around $100), but labor costs are not that much. Boxer engines are wide, so many mechanics will completely remove the engine for this repair.
Subaru Short Block
To access the cylinder head gasket, the mechanic must disassemble the engine down to the short block. They usually replace both seals at the same time. If one head gasket leaks, the other will usually leak soon after as well.
If your car is in the shop for a head gasket repair, and you’re not sure when they last replaced it, you should also have them replace the timing belt, water pump, idler pulley, camshaft seal, both main seals, and the front transmission gasket.
You don’t want to incur additional costs on top of an already expensive repair bill, but these parts are relatively inexpensive and usually hard to come by. There’s no best time to replace them. This strategy could save you money in the long run.
Can I do this job myself? Whether or not you can do this job yourself depends on a few factors. Before you begin, you need to be honest with yourself about your mechanical abilities and weigh the pros and cons.
Estimated Downtime
For your new cylinder head gasket to last a long time, the head must be perfectly flat and smooth. If this is a car you use daily and you don’t have a spare car, you probably don’t want to do this job yourself.
Replacing a cylinder head gasket is very time-consuming. This is not for the faint of heart, nor is it something you can tackle in a weekend.
The lead time for this step alone can be several days, or even longer if the workshop is busy. If the valves are in good condition, allow extra time and money to have them worked on.
Tools Required
You will need some special tools that you may not have, such as: B. A torque angle measuring device and a motor crane (also called an aerial work platform). An impact wrench will make certain jobs, like removing the crankshaft belt bolts, much easier.
A quality torque wrench is a must. You’ll also need a socket set and some extension and universal joint sockets to access the fasteners in the bellhousing. Don’t forget your factory service manual.
Follow your factory service manual carefully. The order in which you tighten cylinder heads is very specific, and torque specs are not the same for all models.
If you know what you’re doing, you should be able to buy all the tools you need for less than it would cost to go to the store. Plus, it’s a great excuse to convince your partner that it’s time to pack your garage with some great new tools.
Further Considerations
This can cause extensive damage that may require a complete engine replacement in the worst case scenario. If you’ve never replaced a timing belt before or are nervous about this risk, it’s best to leave this task to a professional.
Before you buy one, make sure you have the patience, money for tools, and a clean, dry work space. If you’re not comfortable with this, it’s a good idea to get a security-conscious friend to help you.
Keep in mind that few mechanics are happy to show up with your car on a flatbed and a pile of parts scattered inside because you overdid it. Before tackling the work yourself, do your research to make sure you’re truly up to the task.
Still, it’s important to stay on the lookout for recalls affecting your specific Subaru model, as other related issues may indirectly affect the lifespan of your head gasket.
Subaru has issued service bulletins to its dealer network. These bulletins provide important information to diagnose and solve common sealing problems. These helpful pieces of information can help technicians and mechanics understand the details of the problem and effectively help them repair your vehicle.
How can I prevent a Subaru head gasket failure? There is no way to eliminate the risk of a Subaru head gasket failure, but taking good care of your engine and following the manufacturer’s recommended maintenance schedule can help.
– Check your coolant level regularly to make sure it is at the correct level. – Change engine oil and filters at recommended intervals. This keeps the engine well lubricated and cooled.
– Use high-quality engine coolant and engine oil that meet Subaru specifications for your vehicle model.
– Prevent the engine from overheating by monitoring the temperature gauge and correcting any problems immediately.
– Check the radiator and cooling system for leaks or damage. A faulty cooling system can cause the engine to overheat and damage the cylinder head gasket.
– If you notice any signs of a head gasket problem, such as: coolant in the oil, white smoke coming from the exhaust, or a sudden decrease in coolant, have it checked by a professional mechanic as soon as possible.
– Is it worth repairing my old Subaru’s head gasket? – Whether it’s worth repairing your old Subaru’s cylinder head gasket depends on several factors.
