How to Replace the Fuel Cap on a 2018 Cadillac XT5 (Fix EVAP Leaks & Check Engine Light)
Step-by-step fuel cap replacement with required tools/parts, safety tips, and what to do if codes don’t clear
How to Replace the Fuel Cap on a 2018 Cadillac XT5 (Fix EVAP Leaks & Check Engine Light)
Step-by-step fuel cap replacement with required tools/parts, safety tips, and what to do if codes don’t clear
đź”§ XT5 - Fuel Cap Replacement
Replacing the fuel cap is a quick job that helps your XT5 maintain proper EVAP system sealing (the system that traps fuel vapors). A worn or incorrect cap can cause a check engine light, fuel smell, or “tighten gas cap” messages.
Difficulty Level: Beginner | Estimated Time: 0.1-0.3 hours
⚠️ Safety & Precautions
- ⚠️ Work in a well-ventilated area, away from sparks, cigarettes, or open flames.
- ⚠️ Turn the engine OFF before opening the fuel door.
- ⚠️ Don’t top off the tank after the pump clicks off (can damage EVAP components).
- Battery disconnect is not required.
đź”§ 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 if equipped) - Qty: 1
đź“‹ Before You Begin
- Park on level ground and shift to P.
- Turn the ignition OFF and remove the key/fob from the vehicle.
- If you just drove, wait a few minutes so any tank pressure can settle.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door
- Use your hand to press the fuel door to release it (push-to-open style), then swing it open.
- Use a flashlight to check the area for dirt or damage.
Step 2: Remove the old fuel cap
- Use your hand (with nitrile gloves) to turn the cap counterclockwise until it comes off.
- If your cap has a strap (tether), let it hang without twisting it.
- Tip: Go slow if you hear a hiss.
Step 3: Inspect and clean the sealing area
- Use a flashlight to inspect the filler neck sealing surface (the round lip the cap seals against).
- Use a shop towel to wipe away dust or grit. Don’t push debris into the opening.
Step 4: Install the new fuel cap
- Place the new cap onto the filler neck and turn it clockwise by hand.
- Keep turning until it is fully tight; most OEM-style caps will “click” when correctly tightened (that click is a built-in clutch so you don’t overtighten).
- Tip: If it doesn’t click, keep snugging by hand.
Step 5: Close the fuel door
- Push the fuel door closed until it latches flush with the body.
âś… After Repair
- Start your XT5 and confirm there are no fuel smells around the fuel door area.
- If you had a check engine light related to the cap/EVAP, it may take a few drive cycles to clear on its own; a scan tool can clear codes immediately.
- Re-check the cap after your next fill-up to ensure it’s still tightening/clicking normally.
đź’° 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 0.1-0.3 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.
















