How to Replace the Fuel Cap on a 2018 Jeep Grand Cherokee
Step-by-step DIY guide with tools, safety tips, EVAP leak checks, and cost savings
How to Replace the Fuel Cap on a 2018 Jeep Grand Cherokee
Step-by-step DIY guide with tools, safety tips, EVAP leak checks, and cost savings
🔧 Grand Cherokee - Fuel Cap Replacement
Replacing the fuel cap on your Grand Cherokee is a very simple repair. A loose, cracked, or worn fuel cap can cause fuel vapor leaks and may trigger a check engine light with an EVAP system fault.
Difficulty Level: Beginner | Estimated Time: 5-10 minutes
⚠️ Safety & Precautions
- ⚠️ Work in a well-ventilated area and keep flames, cigarettes, and sparks away from the fuel filler area.
- ⚠️ Do not replace the fuel cap while fueling.
- ⚠️ Wipe up any fuel spills immediately with a clean shop towel.
- ⚠️ Battery disconnect is not required for this repair.
🔧 Required Tools
You'll need the following tools for this repair:
- Nitrile gloves
- Safety glasses
- Clean shop towel
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Fuel cap - Qty: 1
📋 Before You Begin
- Park your Grand Cherokee on level ground.
- Shift to Park and apply the parking brake.
- Turn the ignition completely off.
- Make sure the replacement fuel cap matches your Grand Cherokee’s cap style and sealing design.
- The fuel cap seals the fuel tank vapor system. This system is called EVAP, which means evaporative emissions control.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the Fuel Door
- Use your hand to press and open the fuel filler door on the driver-side rear quarter panel.
- Put on nitrile gloves and safety glasses before touching the fuel cap area.
- Use a clean shop towel to wipe dirt away from around the fuel cap before removal.
- Keep dirt out of the filler neck.
Step 2: Remove the Old Fuel Cap
- Use your hand to turn the old fuel cap counterclockwise until it releases.
- If your cap has a tether, the tether is the small plastic strap that keeps the cap attached to the fuel door area.
- Use your hand to unclip the tether from its mounting point if the replacement cap includes a new tether.
- Do not use pliers or metal tools on the fuel cap. They can damage the filler neck or create sparks.
Step 3: Inspect the Fuel Filler Neck
- Use a clean shop towel to gently wipe the sealing surface where the cap contacts the filler neck.
- Look for dirt, rust, cracks, or damage on the filler neck sealing surface.
- If the surface is dirty, wipe it clean with the clean shop towel.
- A clean seal prevents EVAP leaks.
Step 4: Install the New Fuel Cap
- Use your hand to place the new fuel cap squarely onto the filler neck.
- Turn the cap clockwise until it clicks.
- Continue turning until you hear at least one clear click.
- No torque wrench is used for this repair. The clicking sound means the cap is properly tightened.
Step 5: Secure the Tether and Close the Fuel Door
- Use your hand to attach the tether to its mounting point if the new cap uses one.
- Make sure the tether is not pinched between the cap and the fuel door.
- Close the fuel door firmly by hand.
✅ After Repair
- Start your Grand Cherokee and confirm there is no fuel smell around the filler area.
- If the check engine light was on for a loose or leaking fuel cap, it may take several drive cycles to turn off by itself.
- A drive cycle means a normal engine start, warm-up, drive, and shutdown.
- If you have a basic scan tool, you may clear the EVAP-related code after replacing the cap.
- If the check engine light returns, the EVAP leak may be from another part, such as a purge valve, vent valve, hose, or leak detection pump.
💰 DIY vs Shop Cost
Shop Cost: $60-$140 parts + labor/diagnostic time
DIY Cost: $15-$35 parts only
You Save: $45-$105 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 if no further EVAP diagnosis is needed.
🎯 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.
















