How to Replace the Fuel Cap on a 2020 Chevrolet Blazer (Fix EVAP Leak & Check Engine Light)
Step-by-step fuel cap replacement with tools, parts tips, safety notes, and how to clear EVAP-related codes
How to Replace the Fuel Cap on a 2020 Chevrolet Blazer (Fix EVAP Leak & Check Engine Light)
Step-by-step fuel cap replacement with tools, parts tips, safety notes, and how to clear EVAP-related codes
š§ Blazer - Fuel Cap Replacement
Replacing the fuel cap on your Blazer is a quick job: you remove the old cap and install a new one that seals correctly. A good seal prevents fuel vapors from escaping and can stop an EVAP-related check engine light caused by a loose or failed cap.
Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours
ā ļø Safety & Precautions
- ā ļø Work with the engine OFF and away from sparks, cigarettes, or open flames.
- ā ļø Donāt replace the cap right after driving if you smell strong fuel vaporsālet it sit a few minutes.
- ā ļø Do not use oils/grease on the cap seal; it can damage the rubber and cause leaks.
- Battery disconnect is not required.
š§ Required Tools
You'll need the following tools for this repair:
- Nitrile gloves
- Flashlight
- Clean shop towel
š© Required Parts
HowToo sells all the parts you need for this repair:
- Fuel cap (OEM-style, tethered) - Qty: 1
š Before You Begin
- Park your Blazer on level ground and shift to P.
- Turn the ignition OFF and remove the key/fob from the vehicle.
- If the fuel door is locked, unlock the doors first.
šØ Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door
- Use a flashlight if itās dark to clearly see the cap area.
Step 2: Remove the old fuel cap
- Put on nitrile gloves.
- Turn the cap counterclockwise until it releases, then pull it straight off.
- If your cap has a tether (a small strap that keeps it from getting lost), let it hang.
Step 3: Inspect and clean the sealing surface
- Use a clean shop towel to wipe the filler neck sealing surface (the flat/ring area the cap presses against).
- Check for dirt, sand, or cracks. Clean seal = no EVAP leaks.
Step 4: Install the new fuel cap
- Align the new cap and push it onto the filler neck.
- Turn the cap clockwise until it is fully tight. On most OEM-style caps youāll feel/hear clicksākeep turning until it stops clicking and feels snug.
- Make sure the tether (if equipped) is not pinched and the cap sits square.
Step 5: Close the fuel door
- Close the fuel door firmly so it latches.
ā After Repair
- Start your Blazer and confirm thereās no fuel smell around the fuel door.
- If you had a check engine light from a loose cap, it may take a few drive cycles to clear on its own; a scan tool can clear it immediately.
- Recheck the cap tightness after your next fill-up.
š° 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.
šÆ 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.
















