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2018 Subaru Legacy
2001 - 2024 Subaru Legacy
Flat 4 2.5L
Compatible with more variants.

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Subaru Crosstrek 2018 Gas Fuel Cap Replacement

Subaru Crosstrek 2018 Gas Fuel Cap Replacement

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Tools & Fluids

Nitrile
Nitrile
Gloves
Cloth Rags
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Flashlight
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How to Replace the Fuel Cap on a 2018 Subaru Legacy (Fix EVAP Leak & Loose Cap Warning)

Step-by-step fuel cap replacement with required tools/parts, safety tips, and what to do if the check engine light stays on for 2001, 2002, 2003, 2004, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024

How to Replace the Fuel Cap on a 2018 Subaru Legacy (Fix EVAP Leak & Loose Cap Warning)

Step-by-step fuel cap replacement with required tools/parts, safety tips, and what to do if the check engine light stays on for 2001, 2002, 2003, 2004, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024

Orion
Orion

🔧 Legacy - Fuel Cap Replacement

The fuel cap seals the fuel tank so fuel vapors don’t leak out and so the EVAP system can work correctly. Replacing it is quick and can fix a loose-cap warning or EVAP leak codes caused by a worn seal.

Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours


⚠️ Safety & Precautions

  • ⚠️ Work in a well-ventilated area, away from flames or smoking.
  • ⚠️ Turn the engine off before opening the fuel door.
  • ⚠️ Don’t over-tighten the new cap; stop after the clicks.
  • Battery disconnect is not required.

🔧 Required Tools

You'll need the following tools for this repair:

  • Nitrile gloves
  • Shop towel
  • Flashlight

🔩 Required Parts

HowToo sells all the parts you need for this repair:

  • Fuel cap (OEM-style, tethered) - Qty: 1

📋 Before You Begin

  • Park on level ground and shut the engine off.
  • Make sure you’re away from open flames and hot surfaces.
  • Wipe dirt off the area around the fuel filler (the metal neck) using a shop towel.

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Open the fuel door

  • Use the flashlight if it’s dark and locate the fuel door on the left rear quarter.
  • Open the fuel door by hand.

Step 2: Remove the old fuel cap

  • Put on nitrile gloves.
  • Turn the cap counterclockwise (left) until it releases, then remove it.
  • If you hear a light “hiss,” that’s normal tank pressure releasing.

Step 3: Inspect and clean the sealing surfaces

  • Use a shop towel to wipe the fuel filler neck sealing surface (the flat rim the cap seals against).
  • Check the old cap’s rubber seal for cracks or flattening. Worn seals cause EVAP leaks.

Step 4: Install the new fuel cap

  • Thread the new cap on by hand and turn it clockwise (right).
  • Keep turning until you hear/feel it click. Tighten until it clicks at least once (up to 3 clicks is fine).
  • Make sure the tether (the small strap) isn’t pinched and the cap sits straight.

Step 5: Close the fuel door

  • Close the fuel door firmly by hand.

✅ After Repair

  • Start the engine and confirm there is no fuel smell around the fuel door area.
  • If you had a “Check Engine” light from a loose cap, it may take a few normal trips to clear on its own.
  • If the light stays on after several trips, you may need an OBD2 scan to confirm the issue wasn’t another EVAP leak.

💰 DIY vs Shop Cost

Shop Cost: $40-$120 (parts + labor)

DIY Cost: $15-$45 (parts only)

You Save: $25-$75 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.2-0.5 hours.


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