23 to 36 gal tank swap: DONE
07-19-2019, 11:37 PM
#1
23 to 36 gal tank swap: DONE
I know a lot of people ask about it, but I've only seen a few posts of people actually doing it. I am hoping to clear the air for people who want to do this. This is the process I went through and hopefully this will help others or convince them they can do it themselves.
Parts List:
All cab/bed configurations have interchangeable fuel tanks, with the exception of the 122" wheelbase truck. For all others, you can use any tank or fuel pump from any other truck. (The one exception is the 5.0L fuel pump. It has a different part number, but I have been told that it still works. I am not sure why that pump is different.) You will need a new pump assembly too, because the fuel level sending unit is different for 23 and 36 gallon tanks. Technically you could try to swap the sending units, but a new pump is just easier. The tanks are very similar looking. If you need to determine which is which, the 23 gallon tank is about 62" long and the 36 gallon tank is 74" long.
I got all of my parts from a local parts yard that I found on Car-Part.com. Several of the yards I found were having mislabeled tanks, so make sure you measure the tank before you buy one. (Click HERE to see a comparison.)
- 36 Gal Fuel Tank: KL3Z-9002-C
- 36 Gal Fuel Pump : FL3Z-9H307-N
If your tank doesn't come with a heat shield, you will need one of those too.
- 36 Gal Tank Heat Shield: FL3Z-9A032-D
All other parts, such as fuel lines, tank straps, fuel pump gasket, fuel pump lock ring, etc, can be reused.
My total cost was $144 for a tank and pump.
Removing the old tank:
Removal of the old tank is by far the most time consuming step. Start with the tank as empty as possible, then place a floor jack under the tank to lift the weight off of the tank straps. Each strap has one 15mm bold. Best to use an impact gun on these. Once you get the straps unbolted, they will hang loose. Just twist them to remove the other end from a slot in the subframe.
Carefully lower the floor jack. The front of the tank should come down a few inches. At the front of the fuel tank are two quick connect fuel lines. Disconnect both. A few ounces of gas will come out of the lines, so maybe have something to catch it in. You can leave the fuel lines connected to the tank's white connectors at this point or if you prefer you can remove them from the tank.
--- (Some people choose to drop the drive shaft to get access to the fuel pump connections at this point. I didn't want to do that, but you could if you want.) ---
Continue lowering the tank to the ground with the rear end of the tank still suspended. It will be held up by a number of fuel lines and electrical connectors. Reach towards the back of the fuel tank and disconnect the various fuel lines and electrical connectors. there are 3 fuel line connectors and 2 electrical connectors. Most of these connectors have a two-step release where you have to unlock a safety lock then press the release clips. The fuel line connectors tend to be fragile, be careful not to break them. This is BY FAR the most tedious process because you have very poor access to the top of the tank.
Leave the filler hose for last, because it is strong enough to hold the weight of a mostly empty tank (unlike the electrical connectors and fuel connectors.) The filler neck is held on with a small hose clamp, 8mm. It's easiest to remove it at the tank, but you could also remove it up top from under the rear wheel well.
With the filler hose disconnected the tank will drop free. Be sure to have a floor jack in place so you can slowly lower it.
CONGRATS! THE HARD PART IS OVER!
Preparing the new tank:
Make sure the new tank is clean and dry inside. If it's used it may have rain water inside. Make sure to get all water out. If you need to install a pump, its not difficult. Look inside the tank and you will see a raised semi-circle. This hold the pump in the tank. There is a quick-connect hose in the tank that goes onto a connector on the bottom of the pump lid pointing down. Place the green gasket between the pump and tank. Insert the pump into the tank, roughly where that semi circle is, then line up the larger plastic tab on the lid with the "Locator" word on the fuel tank. Then place the locking ring in place. It has grooves on the outside for you to place a large flathead screwdriver in and strike with a rubber mallet. The first few will go easy, but then it will take several hard hits to full lock.
If you are reusing fuel lines, fully remove them from the old tank by prying them from the white hold down connectors. Then reinstall them on the new tank. Connect as many of the fuel line connectors to the fuel pump as you can now while it's out of the truck.
Installing the new tank:
This is simply the reverse of removal. Raise the new tank up, and start with the filler neck. Then connect the electrical connectors and any fuel connections you haven't already hooked up to the pump. Then lift the tank the rest of the way with a jack, connect the two fittings at the front of the tank to the rest of the fuel system. Reinstall the fuel tank straps and tighten down the bolts with an impact.
Preparing the truck:
Put some fuel in the new tank once it is installed. I put in 2 gallons and that was plenty. Cycle the key several times to get the fuel pump primed then start it up. Mine hesitated for a moment after running for a few seconds, but it picked right back up.
Your fuel gauge will read correctly, but the DTE will be wrong until you reprogram the computer with Forscan. I will have a separate post about that. (EDIT: Forscan update in Post #13)
Here is a video of my process. Unfortunately, the SD card I was using got corrupted, so I lost a lot of the files, so I wasn't able to make a "step by step" video, but it will at least give you an idea of what it takes. (Spoiler: Its not much. Anyone can do this.)
Parts List:
All cab/bed configurations have interchangeable fuel tanks, with the exception of the 122" wheelbase truck. For all others, you can use any tank or fuel pump from any other truck. (The one exception is the 5.0L fuel pump. It has a different part number, but I have been told that it still works. I am not sure why that pump is different.) You will need a new pump assembly too, because the fuel level sending unit is different for 23 and 36 gallon tanks. Technically you could try to swap the sending units, but a new pump is just easier. The tanks are very similar looking. If you need to determine which is which, the 23 gallon tank is about 62" long and the 36 gallon tank is 74" long.
I got all of my parts from a local parts yard that I found on Car-Part.com. Several of the yards I found were having mislabeled tanks, so make sure you measure the tank before you buy one. (Click HERE to see a comparison.)
- 36 Gal Fuel Tank: KL3Z-9002-C
- 36 Gal Fuel Pump : FL3Z-9H307-N
If your tank doesn't come with a heat shield, you will need one of those too.
- 36 Gal Tank Heat Shield: FL3Z-9A032-D
All other parts, such as fuel lines, tank straps, fuel pump gasket, fuel pump lock ring, etc, can be reused.
My total cost was $144 for a tank and pump.
Removing the old tank:
Removal of the old tank is by far the most time consuming step. Start with the tank as empty as possible, then place a floor jack under the tank to lift the weight off of the tank straps. Each strap has one 15mm bold. Best to use an impact gun on these. Once you get the straps unbolted, they will hang loose. Just twist them to remove the other end from a slot in the subframe.
Carefully lower the floor jack. The front of the tank should come down a few inches. At the front of the fuel tank are two quick connect fuel lines. Disconnect both. A few ounces of gas will come out of the lines, so maybe have something to catch it in. You can leave the fuel lines connected to the tank's white connectors at this point or if you prefer you can remove them from the tank.
--- (Some people choose to drop the drive shaft to get access to the fuel pump connections at this point. I didn't want to do that, but you could if you want.) ---
Continue lowering the tank to the ground with the rear end of the tank still suspended. It will be held up by a number of fuel lines and electrical connectors. Reach towards the back of the fuel tank and disconnect the various fuel lines and electrical connectors. there are 3 fuel line connectors and 2 electrical connectors. Most of these connectors have a two-step release where you have to unlock a safety lock then press the release clips. The fuel line connectors tend to be fragile, be careful not to break them. This is BY FAR the most tedious process because you have very poor access to the top of the tank.
Leave the filler hose for last, because it is strong enough to hold the weight of a mostly empty tank (unlike the electrical connectors and fuel connectors.) The filler neck is held on with a small hose clamp, 8mm. It's easiest to remove it at the tank, but you could also remove it up top from under the rear wheel well.
With the filler hose disconnected the tank will drop free. Be sure to have a floor jack in place so you can slowly lower it.
CONGRATS! THE HARD PART IS OVER!
Preparing the new tank:
Make sure the new tank is clean and dry inside. If it's used it may have rain water inside. Make sure to get all water out. If you need to install a pump, its not difficult. Look inside the tank and you will see a raised semi-circle. This hold the pump in the tank. There is a quick-connect hose in the tank that goes onto a connector on the bottom of the pump lid pointing down. Place the green gasket between the pump and tank. Insert the pump into the tank, roughly where that semi circle is, then line up the larger plastic tab on the lid with the "Locator" word on the fuel tank. Then place the locking ring in place. It has grooves on the outside for you to place a large flathead screwdriver in and strike with a rubber mallet. The first few will go easy, but then it will take several hard hits to full lock.
If you are reusing fuel lines, fully remove them from the old tank by prying them from the white hold down connectors. Then reinstall them on the new tank. Connect as many of the fuel line connectors to the fuel pump as you can now while it's out of the truck.
Installing the new tank:
This is simply the reverse of removal. Raise the new tank up, and start with the filler neck. Then connect the electrical connectors and any fuel connections you haven't already hooked up to the pump. Then lift the tank the rest of the way with a jack, connect the two fittings at the front of the tank to the rest of the fuel system. Reinstall the fuel tank straps and tighten down the bolts with an impact.
Preparing the truck:
Put some fuel in the new tank once it is installed. I put in 2 gallons and that was plenty. Cycle the key several times to get the fuel pump primed then start it up. Mine hesitated for a moment after running for a few seconds, but it picked right back up.
Your fuel gauge will read correctly, but the DTE will be wrong until you reprogram the computer with Forscan. I will have a separate post about that. (EDIT: Forscan update in Post #13)
Here is a video of my process. Unfortunately, the SD card I was using got corrupted, so I lost a lot of the files, so I wasn't able to make a "step by step" video, but it will at least give you an idea of what it takes. (Spoiler: Its not much. Anyone can do this.)
Last edited by A/Ox4; 07-26-2019 at 02:31 PM.
The following 20 users liked this post by A/Ox4:
1995GreenMachine (07-19-2019),
2016BoostedGreyGoose (08-01-2020),
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and 15 others liked this post.
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Booky (05-25-2022)
07-20-2019, 12:13 AM
#4
That's awesome, I absolutely love having this larger tank. I average around 550 miles before I usually fill up, and have been getting ~18 MPG on my 3.5. If I set it to 55MPH like some crazies on here do I could probably drive 800 miles straight. Nice job, I'm sure you'll enjoy the difference!
The following users liked this post:
TrdLtly (08-23-2021)
07-20-2019, 12:19 AM
#7
That's awesome, I absolutely love having this larger tank. I average around 550 miles before I usually fill up, and have been getting ~18 MPG on my 3.5. If I set it to 55MPH like some crazies on here do I could probably drive 800 miles straight. Nice job, I'm sure you'll enjoy the difference!
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Slvr (07-20-2019)
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07-20-2019, 10:27 AM
#8
The 36 gallon tank is great! It was a must have when I was looking to buy my truck. Pulling my travel trailer with my 06 FX4 with the 26 gallon tank wasn't cool having to stop for gas so often.
