Do Subarus Burn Oil? Causes, Signs, and Prevention Tips

If you own a Subaru or are thinking about getting one you might have heard concerns about oil consumption. Many drivers wonder if Subarus are prone to burning oil and what that means for their vehicle’s health. Understanding this issue can help you maintain your car better and avoid unexpected repairs.

Subarus have a reputation for reliable performance but like any brand some models have shown signs of oil burning under certain conditions. Knowing why this happens and how to spot the signs early can save you time and money. Let’s explore what causes oil burning in Subarus and how you can keep your engine running smoothly.

Understanding Subaru Engines

Subaru engines combine unique designs with specific features that influence oil consumption. Recognizing these characteristics helps you understand why some Subaru models burn oil.

Overview of Subaru Engine Types

Subaru mainly uses two engine types: the Boxer engine and the turbocharged variant. The Boxer engine features horizontally opposed cylinders for a low center of gravity and balanced performance. Turbocharged versions add forced induction for enhanced power but can increase stress on engine components. Both engine types use aluminum blocks and heads to reduce weight, affecting thermal expansion and oil sealing properties.

Common Engine Designs and Features

Subaru engines often include smooth cylinder walls, designed to reduce friction but sometimes affecting oil retention between piston rings and cylinder walls. Their timing chain systems reduce maintenance compared to belts but may loosen over time, influencing valve timing and oil control. Valve stem seals and piston ring designs vary across models; early 2000s to mid-2010s engines often show more oil consumption due to less advanced seal materials. Recent engines use improved ring sets and updated valve stem seals to limit oil burning.

Causes of Oil Burning in Subarus

Oil burning in Subarus occurs for several reasons. Understanding these causes helps you identify whether your vehicle’s oil use lies within normal limits or indicates underlying problems.

Normal Oil Consumption vs. Excessive Burning

Subarus consume some oil under normal conditions, especially within the first 1,000 to 3,000 miles of engine break-in. Engines with turbochargers often burn slightly more oil due to higher operating temperatures and pressures. Using up to one quart every 1,000 to 1,500 miles qualifies as normal consumption for many Subaru models. Excessive oil burning occurs when consumption exceeds this range, leading to frequent oil top-offs or blue exhaust smoke.

Mechanical Issues Leading to Oil Burning

Worn piston rings, degraded valve stem seals, and compromised turbocharger seals cause oil to enter combustion chambers. The aluminum engine blocks used in Subarus expand differently under heat, affecting oil sealing if components wear prematurely. Loose timing chains and cylinder walls smoothness can also contribute by allowing oil seepage. Early model engines from the 2000s to mid-2010s face higher risks due to less advanced materials used in seals and rings.

Impact of Driving Habits and Maintenance

Aggressive driving increases engine temperature and oil consumption by stressing seals and rings. Frequent short trips prevent proper engine warming and oil circulation, exacerbating oil burning. Neglecting regular oil changes leads to sludge buildup, which degrades seal effectiveness and accelerates wear. Using manufacturer-recommended oil types and grades ensures proper lubrication and reduces oil burning risks.

Models and Years Prone to Oil Burning

Certain Subaru models and production years experience more oil burning than others. Knowing which ones helps you anticipate potential maintenance needs and monitor oil levels effectively.

Known Issues in Specific Subaru Models

Subaru vehicles from the early 2000s through the mid-2010s, especially those with 2.5L Boxer engines, show higher oil consumption. Examples include the Legacy (2002-2009), Outback (2005-2009), and Forester (2004-2012). Turbocharged versions of these models, such as the WRX and STI from 2008 to 2014, also face increased oil burning risk due to added engine stress. Worn piston rings and valve stem seals in these engines often cause oil leakage into combustion chambers. Newer Subaru models after 2015 feature improved ring designs and enhanced valve seals that significantly reduce oil consumption.

Recalls and Manufacturer Responses

Subaru issued several recalls and service bulletins addressing oil burning in affected models. Notably, the 2011-2014 Subaru WRX and STI received extended warranties on engines with high oil consumption rates. The manufacturer introduced revised piston rings and cylinder sleeve replacements for some legacy and Outback models between 2008 and 2014. Subaru also enhanced oil control measures in newer engines, limiting oil consumption to within industry standards. Checking for open recalls and manufacturer service updates for your specific model year helps you stay informed and maintain your Subaru’s engine health.

Detecting and Diagnosing Oil Burning

Detecting oil burning in your Subaru early prevents severe engine damage and costly repairs. Identifying clear signs and performing regular checks helps maintain optimal engine performance and longevity.

Signs Your Subaru Is Burning Oil

Watch for these signs that indicate oil burning in your Subaru:

• Blue-gray exhaust smoke: Visible during acceleration or startup, signaling oil entering combustion chambers.
• Frequent low oil level warnings: Alerts despite regular top-offs suggest excessive consumption.
• Strong burnt oil smell: Noticeable inside or around the vehicle, especially after driving.
• Engine misfires or rough idling: Oil deposits on spark plugs impair ignition performance.
• Excessive oil consumption between changes: Rates exceeding 1 quart every 1,000 miles indicate abnormal burning.

Monitor these signs carefully, as early detection allows timely intervention before engine wear worsens.

How to Check Oil Levels and Quality

Check oil levels every 1,000 miles or monthly using these steps:

• Park on a level surface and turn off the engine.
• Wait at least 5 minutes to allow oil to settle.
• Pull out the dipstick, wipe clean, then reinsert fully.
• Remove the dipstick again and observe the oil level relative to the marked range.

Assess oil quality by noting:

• Color: Healthy engine oil is amber or light brown; dark or black oil with debris signals contamination.
• Consistency: Sludgy or gritty texture indicates breakdown or engine issues.
• Smell: A strong burnt odor suggests overheating or oil deterioration.

Regularly checking oil level and quality reveals early symptoms of burning and supports proactive engine maintenance.

Preventing and Fixing Oil Burning

Addressing oil burning in your Subaru requires a combination of proactive maintenance and timely repairs. Understanding the best practices to minimize oil consumption and the available solutions for common issues helps maintain your engine’s performance and longevity.

Maintenance Tips to Minimize Oil Consumption

• Regularly check oil levels using the dipstick; low levels indicate consumption and demand immediate attention.
• Change oil and oil filters at intervals recommended by Subaru, typically every 6,000 miles or 6 months, whichever comes first.
• Use Subaru-approved synthetic oils with the correct viscosity grade, such as 5W-30 or 0W-20, depending on your model and climate.
• Avoid aggressive driving habits like rapid acceleration and high RPMs, which increase engine stress and oil consumption.
• Monitor engine performance and exhaust smoke color; blue or gray smoke signals oil burning that needs early intervention.
• Inspect air filters and replace worn components to ensure clean air intake, reducing engine strain and oil residue buildup.
• Maintain cooling systems to prevent overheating, which can degrade seals and gaskets, leading to oil leaks and burning.

Repairs and Solutions for Oil Burning Problems

• Replace worn piston rings to restore proper compression and prevent oil from entering combustion chambers.
• Renew valve stem seals and guides to stop oil seepage around valves, a common cause of oil burning in older models.
• Inspect and service turbocharger seals on turbocharged Subaru models to fix oil leaks into the intake system.
• Conduct a leak-down or compression test to diagnose internal engine wear accurately.
• Perform engine decarbonization services if excessive deposits cause poor sealing and increased oil consumption.
• Address timing chain tensioner issues promptly, as slack can harm engine timing and contribute to oil burning.
• Consult Subaru dealerships regarding any recalls or service bulletins relevant to your model, ensuring warranty coverage or updated repairs.
• Consider replacing the PCV (positive crankcase ventilation) valve if clogged or malfunctioning since it affects crankcase pressure and oil management.

Conclusion

Knowing how your Subaru handles oil consumption helps you stay ahead of potential engine problems. By keeping an eye on oil levels and recognizing early warning signs, you can protect your engine from costly damage.

Regular maintenance and using the right oil make a big difference in reducing oil burning. If you notice anything unusual, don’t hesitate to get a professional diagnosis to keep your Subaru running smoothly for years to come.