The 3 Most Common Subaru Head Gasket Issues

Subaru vehicles have earned a reputation for their reliability and performance. However, like any brand, they can experience mechanical issues as they age. 

One of the common concerns that Subaru owners may encounter is head gasket problems. 

This article delves into how to diagnose and fix these issues. We’ll also discuss when to consult a trusted mechanic for professional assistance.

blown Subaru head gasket

Common Issues With Subaru Head Gaskets

Subaru head gaskets are crucial engine components that seal the gap between the cylinder heads and the engine block. Their job is to prevent the mixing and leaking of oil and coolant while also maintaining compression and combustion in the cylinders. 

However, certain Subaru models have experienced head gasket issues that can cause severe engine damage if left unaddressed. 

There are three main types of head gasket problems that impact Subaru engines: external oil leaks, internal coolant leaks, and warped or cracked heads. 

Each type has its own symptoms, causes, and solutions, and they may affect different models depending on the engine type. Here is a summary of each type of problem:

1. External Oil Leaks

This problem occurs when oil seeps out from the gap between the head and the block, resulting in oil dripping from the engine, lower oil levels, and increased risk of fire. 

This is more common on older models with 2.5-liter EJ25 SOHC engines, such as:

  • 1999-2010 Forester
  • 1999-2011 Impreza
  • 2000-2009 Outback
  • 2000-2009 Legacy
  • 2003-2005 Baja

The possible causes of this problem include:

  • Low-quality head gasket material
  • Poor engine maintenance
  • Bad head gasket design
  • Bad water jacket design
  • Detonation
  • Improper head torque procedures
  • Electrolysis of the coolant due to poor grounding

Not fixing this issue can cause low oil pressure, increased oil consumption, and fire hazards. Read more about the signs of a Subaru oil leak. 

2. Internal Coolant Leaks

This occurs when coolant leaks into the combustion chambers through the gap between the head and the block, resulting in white smoke from the exhaust, overheating, loss of power, and engine failure. 

This problem is more common on newer models with 2.5-liter EJ25 DOHC engines from 2006 to 2014, such as:

  • Forester
  • Impreza
  • Outback
  • Legacy

If this problem is not fixed in time, it can lead to overheating, white smoke, loss of power, and engine failure.

Check out the 6 Most Common Subaru Coolant Leaks here. 

3. Warped or Cracked Heads

Cracked heads occur when the heads become distorted or damaged due to overheating, detonation, improper torque procedures, or poor-quality materials.

This can result in compression loss, misfires, rough idle, poor performance, and increased emissions. 

This problem can affect any model with any engine type. Still, it may be more likely on models that have experienced overheating or detonation due to age or lack of maintenance. 

Failing to address this issue promptly can result in complications, including reduced compression, misfiring, an uneven idle, diminished performance, and an uptick in emissions.

5 Signs That Your Subaru Head Gasket Is Failing

Here are some common signs that your Subaru’s head gasket might be failing:

1. Overheating Engine

If you’ve noticed your engine consistently overheating, it’s a potential indicator of a head gasket issue. 

Higher-than-normal temperature readings on your gauge could indicate that the head gasket isn’t providing an effective seal. 

A compromised seal can result in coolant leakage and subsequent engine overheating.

2. Coolant Leaks

If you frequently find yourself replenishing coolant or discovering puddles of coolant beneath your vehicle, it’s a clear indication of a potential head gasket problem.

The head gasket’s primary role is to tightly seal the engine block and cylinder heads, preventing the unwanted mixing of coolant and engine oil. A compromised head gasket can disrupt this seal, leading to coolant leaks.

3. White Exhaust Smoke

The sight of thick white smoke billowing from your exhaust pipe, particularly after the engine has warmed up, should raise alarms about a potential head gasket issue. 

This type of smoke is often a result of coolant making its way into the combustion chamber, where it’s burned alongside the fuel.

4. Oil Contamination

If you’ve noticed an unusual milky or frothy appearance of the oil on your dipstick or oil cap, it could be due to coolant mixing with the engine oil. 

This contamination typically occurs because a damaged head gasket allows these two fluids to mix improperly.

5. Poor Engine Performance

A compromised head gasket can significantly impact your engine’s performance. You might experience decreased power, rough idling, or difficulty starting the engine. 

These issues arise from the improper combustion caused by coolant or exhaust gases entering the cylinders due to a compromised gasket.

OEM Subaru head gasket

How Can I Fix a Head Gasket Issue on My Subaru?

Fixing a head gasket issue on a Subaru can be a complex and involved process, and it often requires specialized tools, knowledge, and experience.

In some cases, head gasket issues can be exacerbated by loose or unevenly torqued bolts. If you have the necessary tools and experience, you might consider checking and tightening the bolts yourself. 

However, this should be done with caution and according to the manufacturer’s specifications. Check steps specific to your model to ensure you do it correctly and don’t break something in the process.

If you don’t feel comfortable doing repairs on your car, it’s better to bring it to an experienced mechanic.

auto mechanic inspects car

When to Bring Your Car to a Trusted Subaru Expert

While basic maintenance and monitoring can help prevent and catch potential head gasket issues early, there are instances when it’s best to consult a trusted Subaru expert. Here are some scenarios where seeking professional assistance is highly recommended:

  • Symptoms: If you notice overheating, coolant leaks, white smoke, oil contamination, or poor engine performance, consult a Subaru expert for accurate diagnosis and solutions.
  • Complex repairs: Head gasket fixes require specialized tools and expertise. If you lack experience or tools, trust a Subaru specialist for proper repairs.
  • Preventive care: Regular check-ups with a Subaru specialist catch issues early, preventing escalation. Thorough inspections and preventive measures safeguard your vehicle.
  • Diagnosis confirmation: If you suspect head gasket issues, a Subaru expert can confirm using comprehensive tests, pinpointing the problem accurately.
  • Safe repairs: Professionals ensure safe and effective repairs, minimizing further damage or complications that can impact safety and performance.

Remember, prompt action saves on costly future repairs. Consult a trusted Subaru expert for the health and longevity of your vehicle. 

Basic maintenance helps monitor, but professional expertise accurately diagnoses and fixes issues. Contact a knowledgeable Subaru mechanic or dealership for help with persistent symptoms or complex problems.

How to Avoid Future Subaru Head Gasket Issues

Here are some tips to help you avoid head gasket issues going forward:

Regular Fluid Checks

Keep an eye on your coolant and oil levels. Regularly inspecting these fluids helps you detect any sudden changes that indicate a potential issue.

Cooling System Care

Maintain your vehicle’s cooling system by ensuring the right coolant levels and using the recommended coolant type. This can help prevent overheating, which can contribute to head gasket problems.

Follow Manufacturer Recommendations

Adhere to your Subaru’s recommended maintenance schedule, which includes oil changes, coolant flushes, and overall system checks. Proper maintenance can prevent issues that lead to head gasket problems.

Schedule Subaru At SL Autoworks in North Little Rock Today!

SL Autoworks is the specialist Subaru owners trust. If you need maintenance, repairs, or performance work, schedule your appointment today!

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