Replacing The Fuel Tank On A 2003 Trailblazer: Step-By-Step Guide

If you're looking to replace the fuel tank on your 2003 Trailblazer, you've come to the right place. This is a complex task that requires a lot of steps and some specialised tools, so it's important to be well-prepared. Many owners of this model have reported issues with the fuel tank, including leaks, so you're not alone in needing to undertake this fix. You'll need to gather your tools and materials, including a new fuel tank, and set aside plenty of time to complete the job safely.

Disconnect the negative battery terminal and open the gas cap

Disconnecting the negative battery terminal and opening the gas cap are two of the first steps in changing the fuel tank on a 2003 Trailblazer. This is a detailed and instructive step-by-step guide on how to do this:

First, pop the hood of your Trailblazer and access the fuse box. With the engine running, pull the relay for the fuel pump. The engine will die within a few seconds. Now, crank the engine a few times to relieve the pressure.

Next, disconnect the negative battery terminal. You can do this by locating the negative battery terminal, which is usually black or marked with a "-" symbol, and then using a wrench or socket to loosen the nut that secures the cable to the terminal. Once it's loose, simply pull the cable away from the terminal.

At this point, you can open the gas cap. It's important to note that you should only disconnect the negative battery terminal and open the gas cap after taking the necessary safety precautions and preparing your workspace. Make sure you are in a well-ventilated area, and have eye protection, gloves, and a fire extinguisher nearby. It is also recommended to lay down thick plastic and raise the vehicle with car ramps to catch any fuel spillage.

By following these steps, you will have successfully disconnected the negative battery terminal and opened the gas cap on your 2003 Trailblazer, allowing you to proceed with the next steps in changing the fuel tank.

Remove the cross bar and use a screwdriver to loosen the screw on the fuel filter

To remove the cross bar and use a screwdriver to loosen the screw on the fuel filter of a 2003 Trailblazer, follow these steps:

First, you will need to pop the hood and access the fuse box. With the engine running, pull the relay for the fuel pump. The engine will die within a few seconds. Now, crank the engine a few times to relieve the pressure. Next, disconnect the negative battery terminal and then open the gas cap.

Now, you can remove the cross bar that is in the way of dropping the tank. Use a short Phillips-head screwdriver to loosen the screw on the fuel filter. You will also need to press in on the schrader valve to release any pressure in the lines. Gas may come out of the valve if there is still pressure in the lines.

Have a container ready to catch any gas that comes out of the filter/line connections. To disconnect the fuel lines, simply press in the clips (blue on the filter) and squeeze the other lines. No special tools are needed for these.

Note: You may need to jack up the front driver's side of your Trailblazer to access the fuel filter.

Disconnect the fuel lines

Disconnecting the fuel lines is a crucial step in changing the fuel tank on a 2003 Trailblazer. Here is a detailed guide on how to do it:

First, lay down thick plastic to catch any fuel spillage and raise the vehicle using car ramps. Place wood on the ramps to prevent the metal from digging into the ground or cement. Next, pop the hood and access the fuse box. With the engine running, pull the relay for the fuel pump; the engine will die within a few seconds. Crank the engine a few times to relieve the pressure.

Now, disconnect the negative battery terminal and then open the gas cap. Remove the crossbar that will be in the way when dropping the tank. Using a short Phillips-head screwdriver, loosen the screw on the fuel filter. You also want to press in on the Schrader valve to release any pressure in the lines. Gas may come out of the valve if there is still pressure in the lines.

Have a container ready to catch any gas that comes out of the filter/line connections. To disconnect the fuel lines, simply press in the clips (which are blue on the filter) and squeeze the other lines. No special tools are needed for this step.

Note that there are two more lines that must be disconnected: one at the top that may be partially hidden, and another that may be harder to spot. Use a flashlight to ensure you don't miss any connections. Once all the fuel lines have been disconnected, you can proceed to remove the fuel tank.

Loosen the straps using a ratchet and socket

To loosen the straps using a ratchet and socket, you'll first need to open the ratchet all the way using the release catch. The release catch is usually a smaller handle that disengages the ratcheting handle. Once you've done that, pull up the release catch and flip the ratchet fully open. Now, you can thread the strap.

The key part of the ratchet strap system is the mandrel. The mandrel refers to the two metal strips at the bottom of the ratchet where the two metal components meet. To thread the strap, slide it through the opening in the middle of the mandrel.

Once you've threaded the strap, you can start to tighten it. Pull the ratchet handle back and forth to do this. Keep ratcheting until the strap feels taut and secure. Be careful not to over-tighten, as this could damage the ratchet strap or your cargo.

When you're happy with the tightness, lock the strap securely in the folded (closed) position. Apply pressure to the ratchet until you hear a click. This means that the strap is locked into place. If you don’t hear the click, tug on the strap and buckle to make sure it’s secure.

Remove the fuel tank

To remove the fuel tank from a 2003 Trailblazer, follow these steps:

Firstly, drive the vehicle as much as possible to reduce the amount of fuel in the tank. Lay thick plastic on the ground (to catch any fuel spills) and raise the vehicle using car ramps with wooden supports. Next, pop the hood and access the fuse box. With the engine running, pull the relay for the fuel pump—the engine will then die within a few seconds. Crank the engine a few times to relieve pressure, then disconnect the negative battery terminal and open the gas cap.

Remove the cross bar that will be in the way for dropping the tank. Loosen the screw on the fuel filter using a short Phillips screwdriver. You also want to press in on the Schrader valve to release any pressure in the lines—be ready to catch any fuel that comes out of the filter/line connections using a container. To disconnect the fuel lines, simply press in the clips (blue on the filter) and squeeze the other lines.

Place a jack and a piece of wood under the tank for support, then loosen the hose from the tank to the gas filler tube. Loosen the straps using a size 15 socket, extension, and 1/2-inch ratchet. Once the straps are removed, the jack and wood will help hold the tank. You may have to jiggle the rearmost strap to get it out of the way.

Lower the tank a little at a time, checking for electrical connections as you go. There should be one located by the driver's rear tire, and another at the rear right corner of the tank. Once you have disconnected all electrical connections, lower the tank further and remove it, sliding it out. You may have to turn the tank a bit to clear the frame.

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