2020 Subaru Outback Burning Oil: Causes, Fixes & What to Expect

Are you frequently topping off your oil between scheduled changes? If your 2020 Subaru Outback is burning oil, it can be a concerning issue, leading to reduced engine life and potential breakdowns. This article will guide you through understanding why your Outback might be consuming excessive oil, how to identify the problem, and what steps you can take to resolve it.

What drivers notice on this 2020 Subaru Outback

Drivers of a 2020 Subaru Outback experiencing excessive oil consumption often report a distinct set of observations that signal a problem is developing or already present.

• Frequent Oil Top-Offs: The most common and immediate sign is needing to add a quart or more of oil every few thousand miles, well before the recommended oil change interval.
• Low Oil Warning Light: The dashboard oil pressure or low oil level warning light may illuminate, especially during turns or hard braking, indicating a critically low oil level.
• Burning Oil Smell: A noticeable odor of burning oil, either inside the cabin through the vents or outside the vehicle, particularly after driving or when the engine is hot.
• Blue or Grayish Exhaust Smoke: Smoke emanating from the exhaust pipe, often most visible during cold starts, hard acceleration, or after prolonged idling.
• Engine Noises: Unusual engine sounds like ticking, knocking, or a general increase in engine noise, which can be a symptom of inadequate lubrication due to low oil levels.
• Sooty Exhaust Tip: The tailpipe may appear unusually dark and sooty, indicating oil is being burned in the combustion chambers.

At a glance: difficulty, repair cost, and diagnostic workflow

• Difficulty Rating: 6/10 — Easy to moderate
• Common Symptoms: Visible Blue or Grayish Smoke: This is a classic sign of oil being burned in the combustion chamber. Blue smoke typicall; Persistent Burning Odor: The smell of burning oil can be caused by leaks dripping onto hot exhaust components or by oil ; Rapidly Decreasing Oil Level: Monitoring your dipstick regularly will confirm if your oil level is dropping more quickly; Illuminated Oil Warning Light: While not always indicating burning oil, a low oil light means the engine is critically l
• Estimated Repair Cost: $100–$800 (parts + typical shop labor)
• OEM Tooling Required: Standard OBD-II scanner and hand tools

Diagnostic workflow:

1. Confirm the symptom on your vehicle.
2. Scan for stored or pending codes with an OBD-II tool.
3. Inspect the most common causes in this guide (visual checks first).
4. Run verification tests before replacing parts.
5. Repair, clear codes, and verify on a test drive.

Symptoms and warning signs

Identifying the specific symptoms early can help prevent more severe engine damage. Pay close attention to these indicators:

• Visible Blue or Grayish Smoke: This is a classic sign of oil being burned in the combustion chamber. Blue smoke typically appears on startup (worn valve seals) or under acceleration (worn piston rings).
• Persistent Burning Odor: The smell of burning oil can be caused by leaks dripping onto hot exhaust components or by oil burning internally.
• Rapidly Decreasing Oil Level: Monitoring your dipstick regularly will confirm if your oil level is dropping more quickly than expected for your mileage and driving habits.
• Illuminated Oil Warning Light: While not always indicating burning oil, a low oil light means the engine is critically low and needs immediate attention.
• Engine Performance Issues: In severe cases, excessive oil consumption can lead to fouled spark plugs, resulting in misfires, rough idling, reduced power, and decreased fuel economy.
• Oil Leaks: While not burning, external oil leaks can contribute to low oil levels and may be mistaken for internal consumption. Always check for visible leaks around the engine.

How to verify and confirm the issue

Confirming that your 2020 Subaru Outback is indeed burning oil, rather than just leaking it, requires a systematic approach. This is crucial before attempting any repairs.

• Perform a Controlled Oil Consumption Test: This is the most definitive method. Top off your oil to the full mark, record the mileage, and drive normally. After a set mileage (e.g., 1,000 miles), recheck the oil level precisely. Documenting this over several intervals can establish a consumption rate. Many Subaru dealerships can perform a formal version of this test.
• Thorough Visual Inspection for Leaks: Before assuming internal burning, meticulously check the entire engine for external oil leaks. Common leak points include:
  • Valve covers
  • Oil pan gasket
  • Front and rear main seals
  • Oil filter housing
  • PCV valve and hoses
  • Turbocharger oil lines (on 2.4L turbo models)
• Observe Exhaust Smoke Characteristics: Pay attention to when the smoke appears:
  • On startup: Often points to worn valve seals, as oil seeps past them when the engine is off.
  • Under acceleration: Can indicate worn piston rings or issues with the PCV system.
  • Constant smoke: Suggests a more severe internal engine problem.
• Check Spark Plugs: Remove and inspect the spark plugs. Oil-fouled plugs (black, oily residue) are a strong indicator of oil burning in the combustion chambers. For more information on general engine issues, see our All repair guides.
• PCV System Inspection: Check the Positive Crankcase Ventilation (PCV) valve and its hoses for clogs or damage. A malfunctioning PCV system can lead to increased crankcase pressure, forcing oil past seals or into the intake.
• Compression and Leak-Down Test: These diagnostic tests measure the integrity of your engine's cylinders. Low compression or excessive leak-down can pinpoint worn piston rings, damaged cylinder walls, or faulty valves, all of which can cause oil burning.

What is different on this year and model

The 2020 Subaru Outback marked the introduction of the sixth generation, bringing significant updates, including new engine options. This model year features two primary engines:

• 2.5L Naturally Aspirated (FB25D): This engine is an updated version of the FB series, known in previous generations for some oil consumption tendencies. While improvements were made for the 2020 model, issues can still arise, often related to PCV systems or long-term wear.
• 2.4L Turbocharged (FA24F): This new engine, derived from the FA20 found in the WRX, offers more power. Turbocharged engines inherently have more components that can contribute to oil consumption, such as turbocharger seals and bearings, which can allow oil into the intake or exhaust if they fail. While generally robust, these specific components are unique to the turbo model.

While Subaru has generally addressed widespread oil consumption issues seen in some earlier generations, individual vehicles can still develop problems due to manufacturing variations, maintenance history, or specific component failures. Therefore, a thorough diagnosis is always necessary.

Common causes (most likely first)

Excessive oil consumption in a 2020 Subaru Outback can stem from several issues, ranging from minor to major engine problems:

• Worn Piston Rings: Over time, the piston rings (especially the oil control rings) can wear out or become clogged with carbon deposits, preventing them from properly scraping oil off the cylinder walls. This allows oil to enter the combustion chamber and burn.
• Worn Valve Seals: These small seals prevent oil from seeping down the valve stems into the combustion chamber. When they harden or crack, oil can leak past them, particularly noticeable on engine startup.
• PCV (Positive Crankcase Ventilation) System Malfunction: A clogged or stuck PCV valve or damaged PCV hoses can lead to excessive crankcase pressure, forcing oil past seals or into the intake manifold, where it is then burned.
• Turbocharger Issues (2.4L Turbo only): On the turbocharged models, worn seals or bearings within the turbocharger can allow engine oil to leak into either the exhaust housing (burning off as blue smoke) or the compressor housing (entering the intake tract and then the combustion chambers).
• Incorrect Oil Viscosity or Quality: Using an oil that doesn't meet Subaru's specifications (e.g., wrong weight or not synthetic as required) can lead to accelerated wear or increased consumption.
• Infrequent Oil Changes: Neglecting regular oil changes can lead to sludge buildup, which can clog oil return passages and cause piston rings to stick, reducing their effectiveness.

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Step-by-step diagnosis and fixes

Addressing a 2020 Subaru Outback burning oil requires a methodical approach. Start with the simplest checks and progress to more complex diagnostics.

• 1. Diligently Monitor Oil Level: Establish a consistent routine for checking your oil, ideally every 1,000 miles. Note the exact level and the amount needed to top it off. This helps quantify the consumption rate.
• 2. Inspect for External Leaks: Thoroughly clean the engine bay and then drive for a short period. Re-inspect for fresh oil drips or stains around gaskets, seals, and the oil filter. Repair any leaks found; even small leaks can add up.
• 3. Check and Replace PCV Valve: Locate the PCV valve (consult your owner's manual or a service manual). Remove it and shake it; if it doesn't rattle, it's likely clogged and needs replacement. Also, inspect the PCV hoses for cracks or blockages.
• 4. Observe Exhaust Smoke: Pay close attention to the timing and color of any smoke from the exhaust. This can help differentiate between valve seal issues (startup smoke) and piston ring issues (acceleration smoke).
• 5. Perform Compression and Leak-Down Tests: These tests are critical for diagnosing internal engine wear. A mechanic can perform these to determine if piston rings or valve seats are failing. Low readings indicate internal engine wear.
• 6. Inspect Turbocharger (2.4L Turbo): If you have the 2.4L turbo engine, inspect the turbocharger for shaft play and oil residue in the intake or exhaust sides. Significant shaft play or oil presence indicates a failing turbo that requires replacement.
• 7. Professional Diagnosis: If initial checks don't pinpoint the problem or if internal engine issues are suspected, it's best to consult a qualified Subaru technician. They have specialized tools and experience to accurately diagnose complex engine problems. You can find more specific model information at the Outback model hub.

Repair options and cost factors

The repair options for a 2020 Subaru Outback burning oil vary widely depending on the root cause, as do the associated costs.

• PCV Valve Replacement: This is often the simplest and least expensive fix. The part itself is inexpensive, and it's a relatively easy DIY job or a quick, affordable repair at a shop.
• Valve Seal Replacement: This is a more involved repair, as it requires removing the cylinder heads or using specialized tools to replace the seals with the heads on. Labor costs can be significant, ranging from moderate to high, in addition to parts.
• Piston Ring Replacement: This is a major engine overhaul, requiring the engine to be partially or fully disassembled to access and replace the pistons and rings. This is a very labor-intensive and costly repair, often approaching the cost of a used engine.
• Turbocharger Replacement (2.4L Turbo): If the turbocharger is the culprit, it will need to be replaced. This is a significant expense, encompassing the cost of a new or remanufactured turbo unit plus substantial labor.
• Engine Replacement or Rebuild: In severe cases of widespread internal engine wear, the most economical solution might be to replace the entire engine with a new, remanufactured, or used unit, or to perform a full engine rebuild. This is the most expensive option.

Cost factors include the specific parts needed, the labor rates of your chosen repair shop, and the extent of the damage. Always get a detailed estimate before proceeding with major repairs.

When to see a professional

While some initial checks can be done at home, there are clear indicators that it's time to seek professional help for your 2020 Subaru Outback burning oil.

• Persistent Blue Smoke: If you continue to see blue smoke from your exhaust despite checking for simple issues like the PCV valve, it strongly suggests an internal engine problem that requires professional diagnosis.
• Rapid Oil Consumption: If your Outback is consuming a quart of oil every 1,000-2,000 miles or less, even after ruling out external leaks, it's a sign of significant internal wear that needs expert attention.
• Engine Noises: Any new or worsening engine noises, such as ticking, knocking, or rattling, especially when combined with low oil levels, indicates a serious issue that could lead to catastrophic engine failure if not addressed promptly.
• Failed Compression or Leak-Down Tests: If you've performed these tests and found low or inconsistent readings, a professional mechanic will be needed to interpret the results and recommend the next steps, which often involve engine disassembly.
• Complex Repairs: Repairs involving valve seals, piston rings, or turbocharger replacement are highly complex and require specialized tools, knowledge, and experience. Attempting these without proper training can lead to further damage.

Frequently asked questions

Is some oil consumption normal for a 2020 Subaru Outback?

Yes, a small amount of oil consumption is considered normal for most modern engines, including the 2020 Subaru Outback, as oil lubricates moving parts and some is inevitably burned off. However,

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