🔧 RDX - Fuel Cap Replacement

The fuel cap seals your fuel system so fumes don’t escape and the EVAP system can self-test correctly. A bad cap can cause a fuel smell and can turn on the Check Engine light (often EVAP leak codes).

Difficulty Level: Beginner | Estimated Time: 0.1-0.3 hours

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⚠️ Safety & Precautions

• ⚠️ Work outside or in a well-ventilated area—fuel vapors are flammable.
• ⚠️ Keep sparks/flames away (no smoking, no drop lights with hot bulbs).
• ⚠️ Don’t top off the tank after the pump clicks off; it can damage the EVAP system.
• ⚠️ Battery disconnect is not required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• Nitrile gloves
• Safety glasses
• Flashlight
• Clean shop towel

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

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

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📋 Before You Begin

• Park on level ground and shift to Park.
• Turn the engine off and remove the key/fob from the vehicle.
• Use a flashlight to look around the fuel door area for dirt or damage.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Open the fuel door

• Press the fuel door to pop it open.
• Use a flashlight if lighting is poor.

Step 2: Remove the old fuel cap

• Turn the cap counterclockwise until it releases.
• If the cap has a tether (the small strap), let it hang—don’t twist the tether.
• Slow turns reduce vapor “whoosh.”

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 clean shop towel to wipe off dust/sand.
• Check the old cap’s rubber seal (gasket). If it’s cracked, flattened, or missing, that can trigger EVAP leaks.

Step 4: Install the new fuel cap

• Thread the new cap on clockwise by hand.
• Keep turning until you hear/feel at least 3 clicks (this is the built-in torque limiter telling you it’s tight enough).
• If your new cap has a tether, make sure it isn’t twisted and won’t pinch in the fuel door.

Step 5: Close the fuel door

• Push the fuel door closed until it latches.
• Use a flashlight to confirm nothing is pinched.

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✅ After Repair

• Start the engine 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 turn off on its own after the EVAP self-test passes.
• If the light stays on, the issue may be elsewhere in the EVAP system (not just the cap).

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💰 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.

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🎯 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.