🔧 RX350 - Fuel Cap Replacement

Replacing the fuel cap on your RX350 is a quick job that helps prevent fuel vapor leaks and can stop an EVAP-related check engine light caused by a weak cap seal.

You’ll remove the old cap, transfer/attach the tether if needed, and install the new cap until it clicks.

Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours

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⚠️ Safety & Precautions

• ⚠️ Work in a well-ventilated area away from flames, sparks, or smoking.
• ⚠️ If the engine was running, wait a few minutes before opening the fuel door to reduce vapor pressure.
• ⚠️ Wipe up any spilled fuel immediately and dispose of rags safely.
• ⚠️ Battery disconnect is not required.

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🔧 Required Tools

You'll need the following tools for this repair:

• Nitrile gloves
• Shop towel
• Flashlight

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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 P.
• Turn the ignition OFF and remove the key/fob from the cabin.
• Have a shop towel ready in case there’s a fuel drip.

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🔨 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 if it’s dark so you can see the cap and tether clearly.

Step 2: Remove the old fuel cap

• Put on nitrile gloves.
• Turn the cap counterclockwise until it releases, then pull it straight off.
• If you see dirt around the filler neck (the metal opening the cap seals to), wipe it with a shop towel. Clean sealing surfaces prevent EVAP leaks.

Step 3: Deal with the tether (if equipped)

• The tether is the small strap that keeps the cap attached to the fuel door area so you don’t lose it.
• If the new cap includes a tether and it’s already attached, leave it as-is.
• If the new cap does not include a tether, move the old tether over if it’s removable, or use the new cap as supplied.

Step 4: Install the new fuel cap

• Place the new cap onto the filler neck and turn it clockwise by hand.
• Keep turning until you hear/feel it click (usually 1–3 clicks). That click is the cap’s clutch telling you it’s tight enough.
• Do not use tools to tighten the cap—hand-tight is correct once it clicks.

Step 5: Close the fuel door

• Use your hand to close the fuel door until it latches.
• Use a shop towel to wipe any fingerprints or fuel residue from the area.

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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 caused by a loose/bad cap, it may take a few drive cycles to clear on its own.
• If the light stays on, the issue may be elsewhere in the EVAP system (like a vent valve or purge valve).

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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 0.1-0.2 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.