How to Replace the Fuel Cap on a 2018 Chevrolet Impala (Fix EVAP Leak & Check Engine Light)
Step-by-step DIY instructions with required tools/parts, safety tips, and what to do if the CEL stays on for 2006
How to Replace the Fuel Cap on a 2018 Chevrolet Impala (Fix EVAP Leak & Check Engine Light)
Step-by-step DIY instructions with required tools/parts, safety tips, and what to do if the CEL stays on for 2006
🔧 Impala - Fuel Cap Replacement
Replacing the fuel cap on your Impala is quick and helps the EVAP system (the system that seals fuel vapors) work correctly. A worn or incorrect cap can trigger a check-engine light and cause a fuel smell.
Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours
⚠️ Safety & Precautions
- ⚠️ Work in a well-ventilated area and keep sparks/flames away from the fuel door.
- ⚠️ Turn the engine OFF before opening the fuel door.
- ⚠️ If you smell strong fuel vapor, stop and let it air out before continuing.
🔧 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 (capless-compatible replacement for your Impala) - Qty: 1
📋 Before You Begin
- Park on level ground and turn the engine off.
- Wipe dirt from around the filler neck with a shop towel so debris doesn’t fall in.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door
- Press the fuel door (or use the release if equipped) and open it.
- Use a flashlight to check the area is clean and not damaged.
Step 2: Remove the old fuel cap
- Put on nitrile gloves.
- Turn the cap counterclockwise until it comes off.
- Set it aside and inspect the rubber seal (gasket). If it’s cracked, flattened, or missing, it can leak vapor.
Step 3: Clean the sealing surfaces
- Use a shop towel to wipe the rim of the filler neck where the cap seals.
- Clean and dry works best for sealing.
Step 4: Install the new fuel cap
- Place the new cap on the filler neck and turn it clockwise.
- Tighten until you hear/feel it click several times (usually 3 clicks). This is the built-in limiter that prevents overtightening.
- Close the fuel door.
✅ After Repair
- Start your Impala and confirm there’s no fuel smell around the fuel door.
- If you had a check-engine light from a loose/bad cap, it may take a few drive cycles to clear on its own. If it doesn’t, scan for codes (common ones are EVAP leak-related).
💰 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 0.1-0.2 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.
















