Changing Fuel Filters: Step-By-Step Guide For Lml Vehicles

Changing the fuel filter on an LML engine can be a challenging task, but it is a necessary one to ensure the engine's performance and longevity. The fuel filter plays a crucial role in preventing contaminants from entering the engine's fuel injectors, which have very close tolerances and can be quickly worn out by dirty fuel. While the process of changing the fuel filter may vary slightly depending on the specific vehicle and model year, there are some general steps and considerations that can be outlined. This includes locating the fuel filter, typically found on the passenger side of the engine, below the air intake tube, and preparing the necessary tools for the job, such as a trim fastener removal tool, socket wrench, and pliers. The process involves draining the fuel from the old filter, carefully removing and replacing the filter, and properly disposing of the drained fuel. It is also important to check for any leaking seals or damage to components such as the water-in-fuel sensor, and to replace any faulty parts during the process. Additionally, it is recommended to prime the new filter after installation and to check for leaks once the engine is started. While it may be tempting to put off changing the fuel filter, regular maintenance is key to keeping the engine in good condition and avoiding more costly repairs down the line.

Drain the water/fuel separator

To drain the water/fuel separator of your LML, start by locating the fuel filter housing, which is on the passenger side of the engine. You will need a 7mm socket, a 10mm socket, and a pair of needle-nose pliers.

First, remove the passenger-side inner fender and/or fender well. This will give you access to the fuel filter. The filter is a big white or black thing with a white drain at the bottom and a wire coming out of it. Unplug the wire and use a pair of channel locks to open the drain cock. You can use an empty water bottle to collect the fluid that comes out. Keep draining until the fluid runs clear.

Once you have drained the separator, carefully tighten the drain cock, making sure not to crack it. Now you can move to the top side of the filter and find the bleeder screw on the filter head. Open the bleeder screw and use the primer bulb until you see solid fuel coming out.

After you have completed these steps, you can put everything back together and your water/fuel separator should be good to go!

Disconnect the water-in-fuel sensor electrical connector

Disconnecting the water-in-fuel sensor electrical connector is a crucial step when changing the fuel filter or fuel filter housing in a Chevy Silverado or GMC Sierra 2500/3500 HD with a Duramax 6.6L diesel engine. Here is a detailed, step-by-step guide on how to perform this task:

Locate the water-in-fuel sensor electrical connector: It is situated near the fuel filter, which is located on the passenger side of the Duramax engine, below the air intake tube.

Access the connector: Before you can disconnect the connector, you will need to remove the center air intake tube between the air filter housing and the turbocharger, as well as the passenger side inner fender. To remove the inner fender, simply remove the plastic body clips and two 10mm bolts holding it in place.

Disconnect the connector: Once you have accessed the water-in-fuel sensor electrical connector, carefully disconnect it. It is important to be gentle during this step to avoid damaging the connector or any surrounding components.

Handle the connector safely: After disconnecting the connector, set it aside in a safe place where it will not be damaged or interfere with your work. Ensure that any wires attached to the connector are handled carefully to avoid accidental damage.

Prepare for the next steps: With the connector safely disconnected, you can now proceed with the rest of the fuel filter replacement process. Refer to the subsequent steps in the fuel filter replacement guide for further instructions.

Reinstallation: When reinstalling the fuel filter, you will need to reconnect the water-in-fuel sensor electrical connector. Ensure that the connector is securely attached before continuing.

It is important to note that working on your vehicle's fuel system can be complex and requires careful attention to safety. Always refer to the vehicle's service manual or seek professional assistance if you are unsure about any steps or procedures.

Remove the fuel filter

To remove the fuel filter from a Chevy Silverado or GMC Sierra 2500/3500 HD, follow these steps:

First, remove the centre air intake tube between the air filter housing and the turbocharger. Then, remove the passenger side inner fender. This is held in place by plastic body clips and two 10mm bolts.

Next, find the water-fuel separator drain valve at the bottom of the fuel filter. Open the bleed screw at the top of the fuel filter housing, then open the water separator drain valve. Drain the water/fuel into a container and dispose of it properly.

Now, disconnect the water-in-fuel sensor electrical connector. Rotate the fuel filter counter-clockwise from the bottom and remove it, keeping it upright to avoid spilling fuel. Drain the remaining fuel from the filter and dispose of it.

Check that the old gasket isn't stuck to the fuel filter head. With a wrench, deep socket, or pliers, remove the water-in-fuel sensor assembly from the bottom of the filter. If the new fuel filter comes with an o-ring for the water-in-fuel sensor assembly, replace the old one with the new one. If the water in the fuel sensor assembly is damaged, it must be replaced. Lubricate the new o-ring with clean engine oil before installing.

Finally, if the new fuel filter comes with a new gasket, replace the old one and lubricate the new gasket with clean engine oil.

Dispose of remaining fuel

It is important to dispose of fuel and filters responsibly, as they can be harmful to the environment. Here are some steps you can take to dispose of any remaining fuel after changing your fuel filter:

Firstly, collect the remaining fuel in a suitable container, such as a jug or old oil container. Do not pour it down the drain or into the environment. You can then take this fuel to an auto parts store or a local waste facility that accepts such materials. Some places that may accept the fuel include Jiffy Lube, Autozone, Advance Auto Parts, and Valvoline Instant Oil Change. It is important to call ahead and check, as not all locations may accept fuel for disposal.

For the fuel filter, allow it to drip for some time to remove any excess fuel. You can then cut open the filter and remove the paper inside, which can be burned. The metal shell of the filter can be disposed of as scrap metal or recycled with other metals. Alternatively, you can crush the filter to squeeze out any remaining fuel before disposal.

If you have access to a waste oil tank, you can also dispose of the fuel in there, as it can be used to feed a heater. This is a common practice in some auto shops. However, it is important to note that fuel should not be disposed of with engine oil, as it can contaminate the oil and render it unusable for recycling.

Finally, always make sure to follow local regulations and guidelines for the disposal of fuels and filters, as there may be specific requirements in your area.

Reinstall the inner fender and intake tube

To reinstall the inner fender and intake tube, follow these steps:

First, locate the packing list included with the kit and double-check that you have all the items on the list. Then, reconnect the factory down pipe or the 3” stainless steel down pipe if you purchased the bundle kit. Tighten the top and bottom v-band clamps.

Next, if your truck has a CP4 still in the valley, you can remove the injector assembly on the passenger valve cover. Once removed, you will need to plug the open port from the CP4 pump. Cut the banjo bolt seal washer from this port in half, so you are left with only one washer instead of a banjo washer. Using a leftover 8mm x 20mm long bolt, reinstall the washer to plug the hole.

Now, locate the small aluminium plug with an O-ring from the supplied parts bag. Install the aluminium plug into the injector return line on the front passenger side. Be careful when retracting the hold-down clip and pushing the new aluminium plug into place, as the plastic clips of the return line are very fragile. Make sure the outer plastic lock is pushed back in place so the plug cannot pop out.

After this, you can move on to the y-bridge install. Locate your new 3” y-bridge and install the factory manifold air pressure (MAP) sensor onto the new y-bridge. The supplied O-rings can also be installed into the grooves on the flanges of the new bridge. If you are not using a mechanical boost gauge or boost pressure sensor, you can use the supplied 1/8” NPT pipe plug and block off the boost port on the new y-bridge.

Now, install the new y-bridge onto the intake runners. ¼” drive swivel sockets and extensions will help with the install. FIRST, get the four lower bolts/nuts started and tighten them evenly side to side in a cross pattern to ensure the bridge seats square to the runners. The LOWER hardware needs to be installed first to suck the bridge down into place before the upper holes will line up. Once the lower bolts/nuts are snug, you can install the four new supplied m6X25mm upper bolts.

Now you can connect the MAP sensor plug on the engine harness back into the MAP sensor on the new y-bridge. As this sensor used to be located on the top of the intake pipe, you will now need to tie down the engine wire harness on top of the engine, pulling it towards the passenger side slightly for the connector to reach the MAP sensor. The wire harness will no longer hang above the engine and can be tied down to the fuel lines.

In the small bag of parts supplied, locate the 5/16” Silicone cap and the matching hose clamp. On the passenger side of the engine, you will find a hard pipe/hose assembly coming from the firewall heater core fitting, forward to a radiator hose. On this pipe, you will find a small port that can be capped off with the cap and hose clamp.

Now, locate the two supplied 3” intercooler boots and four T-bolt clamps. Apply a small amount of grease to the inside leading edge of each 3” boot. Slide one boot onto the intercooler and install the larger of the T-bolt clamps over the boot, tightening the clamp snugly. The second boot needs to be slid onto the y-bridge, all the way up to the 1/8” boost port, so that only about 1” of the boot is hanging off the end of the Y-Bridge. Grease or lubricant is essential for this step, or you will have a very hard time sliding the boot back down in the next step!

Install the OEM temperature sensor from the factory plastic pipe into the bung on your new intercooler pipe. This is NOT a 1/8” boost port; it is metric straight thread for the temp sensor only! The intercooler pipe can now be installed from the top of the engine. Slide the pipe into the lower intercooler boot first, as far as it will go, and then push the pipe against the top boot that is on the y-bridge. With a screwdriver, work the intercooler pipe into the boot. Once it’s in, you can slide the boot back down further onto the pipe so that the boot length is split evenly between the two pipes.

You can now install the remaining T-bolt clamps on both boots and tighten them. Once the lower T-bolts are tight, you can reinstall the air box tray brace to the core support, and the passenger side fender liner.

If you purchased the standard 3” y-bridge kit, locate your new turbo inlet pipe. Install the supplied 1/8” O-ring into your new turbo inlet pipe. Install the factory v-band clamp onto the inlet of the turbo; it is easiest to install this clamp by fully disconnecting it and “rolling” it onto the turbo v-band to sneak it past the y-bridge, as it is a tight fit. Then reconnect the clamp, but leave it loose for now, and slide the new turbo inlet horn into place. Now tighten the v-band clamp, only snug for now, so that you can still adjust the inlet horn.

Locate your OEM intake or WCF 4” intake and install. Adjust the new turbo inlet pipe by twisting it up or down to line up with the intake. Be sure to tighten the clamp at the turbo inlet once it is lined up.

If you purchased the y-bridge kit with a one-piece intake or the high flow bundle kit, locate your new 4” intake pipe. Install the supplied 1/8” O-ring into your new intake pipe flange. Install the four supplied M4 socket head allen screws and reinstall your factory MAF and humidity sensors in the new intake. For 2011 and 2012 trucks, install the supplied aluminium plate on the rectangle sensor port as these model years do not have a humidity sensor.

Install the factory v-band clamp onto the inlet of the turbo; it is easiest to install this clamp by fully disconnecting it and “rolling” it onto the turbo v-band. Then reconnect the clamp, but leave it loose for now. Loosen the passenger side alternator bolt 3-4 turns; you do not need to completely remove it. Install the new 4” intake in the v-band at the turbo first, and then rotate the mount bracket onto the alternator bolt that you just loosened. Once the v-band flange is aligned properly at the turbo, you can first tighten the v-band clamp and then retighten the alternator bolt that holds the intake support bracket.

Finally, install the supplied air filter and outerwear’s filter cover. Refill the engine coolant and start up. After a few initial test drives, it is a good idea to check and retighten all t-bolt and v-band clamps and top off the engine coolant.

Frequently asked questions