How to Replace the Fuel Cap on a 2018 Dodge Durango (Fix EVAP Vapor Leaks)
Step-by-step DIY instructions with required tools/parts, safety tips, and check-engine light verification
How to Replace the Fuel Cap on a 2018 Dodge Durango (Fix EVAP Vapor Leaks)
Step-by-step DIY instructions with required tools/parts, safety tips, and check-engine light verification
đź”§ Durango - Fuel Cap Replacement
Replacing the fuel cap is a quick job that helps prevent fuel vapor leaks (which can trigger a check-engine light) and keeps dirt/water out of the fuel system. On your Durango, the cap should tighten until it “clicks” to seal properly.
Difficulty Level: Beginner | Estimated Time: 0.1-0.3 hours
⚠️ Safety & Precautions
- ⚠️ Work outside or in a well-ventilated area; fuel vapors are flammable.
- ⚠️ No smoking, sparks, or open flames near the fuel door.
- ⚠️ Replace the cap only with the engine OFF.
- ⚠️ If the cap is tethered (attached by a strap), don’t yank the strap.
đź”§ Required Tools
You'll need the following tools for this repair:
- Nitrile gloves
- Safety glasses
- Flashlight
- Clean shop towel
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Fuel filler cap (OEM-style, sealed) - Qty: 1
đź“‹ Before You Begin
- Park on level ground and shift to Park.
- Turn the engine OFF and remove the key/fob from the vehicle.
- If you recently drove, wait a few minutes so any vapor pressure settles.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door
- Use your hand to open the fuel door.
- Use a flashlight to look for dirt or damage around the filler neck opening.
Step 2: Remove the old fuel cap
- Put on nitrile gloves and safety glasses.
- Turn the cap counterclockwise by hand until it comes off.
- If there’s a tether strap, let the cap hang without twisting the strap.
Step 3: Inspect and clean the sealing surface
- Use a flashlight to inspect the rubber seal area on the filler neck (the round surface the cap seals against).
- Wipe the area with a clean shop towel to remove dust/grit.
- Grit on the seal can cause a vapor leak.
Step 4: Install the new fuel cap
- Thread the new cap on by hand (clockwise).
- Tighten until you hear/feel it click (usually 1–3 clicks).
- Do not use tools to tighten—hand-tight is correct.
Step 5: Close the fuel door and verify
- Close the fuel door securely by hand.
- Start the engine and confirm there’s no “GASCAP”/check-engine message related to the cap.
âś… After Repair
- If the check-engine light was on due to a loose/bad cap, it may take a few drive cycles to turn off on its own.
- If the light stays on after several normal trips, the vehicle may have stored an EVAP leak code and may need scanning/diagnosis.
- Make it a habit to tighten the cap until it clicks after every fill-up.
đź’° DIY vs Shop Cost
Shop Cost: $30-$120 (parts + labor/diagnostic)
DIY Cost: $15-$45 (parts only)
You Save: $15-$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.
🎯 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.

















