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Excessive Oil Consumption on my 2018 WRX FA20DIT Engine

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Mike T. · rep 0 · May 25, 2:14 AM · 1 replies · solved · Question

Vehicle: 2018 Subaru WRX Premium

Hey everyone, I've got a 2018 Subaru WRX Premium with the FA20DIT engine, and I'm noticing what seems like excessive oil consumption. I'm having to add about a quart of oil every 1,500-2,000 miles, which feels really high for a car with only 65,000 miles on it.

I haven't seen any visible leaks or smoke from the exhaust, but the dipstick tells the story. Is this a common issue with these FA engines? What should I be looking for? No check engine lights or performance issues yet, but I'm concerned about long-term engine health.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:14 AM

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Excessive oil consumption can be a concern for any engine, and while some level of consumption is normal, adding a quart every 1,500-2,000 miles on a 2018 WRX is definitely on the higher side and warrants investigation. The FA20DIT engine, while generally robust, can experience this.

Here are the common causes and what to consider:

  1. PCV (Positive Crankcase Ventilation) System Issues: A clogged or faulty PCV valve can lead to increased crankcase pressure, forcing oil past piston rings or valve stem seals.
  2. Turbocharger Seals: The turbocharger uses engine oil for lubrication and cooling. Worn or damaged turbo seals can allow oil to enter the exhaust or intake system, where it's burned off without visible leaks.
  3. Piston Rings/Cylinder Walls: While less common on newer FA engines, worn piston rings or cylinder wall scoring can lead to oil blow-by and consumption. This is a more serious internal engine issue.
  4. Valve Stem Seals: Worn valve stem seals can allow oil to leak past the valves into the combustion chamber, especially when decelerating or idling.

What to do:

  • Monitor and Document: Keep a detailed log of oil added, mileage, and driving conditions. This data will be crucial for a technician.
  • Check PCV Valve: Inspect or replace the PCV valve, as it's a relatively inexpensive component that can cause significant oil consumption if faulty.
  • Compression/Leak-Down Test: A shop can perform these tests to assess the health of your piston rings and valves.
  • Turbo Inspection: A mechanic can inspect the turbocharger for shaft play and signs of oil leakage.

When to see a shop: You should schedule a diagnostic appointment soon. While there's no immediate CEL, continued high oil consumption can lead to:

  • Carbon buildup on valves and pistons.
  • Premature catalytic converter failure (P0420 code).
  • Potential engine damage if oil levels drop too low.

Address this proactively to prevent more serious issues down the road.

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