Auxiliary diesel fuel tank Yea or nay

[star1k]

Hello, looking for some recommendations if an additional fuel tank is worth it and what models might be recommended.
I have 36 gallons diesel tank in my car with ~9 gpm this does not give me long range and I was looking to extend it.
I am not looking to replace my spare tire with a tank, I am looking to add one to my truck bed.
I want to put a cover bed, so the tank needs to be less than 21-inch height and ideally have toolbox
I am looking at 90 gallons models.
I am planning to drive ~ 10-12k miles a year, so pay-off time for 2k tank and diesel savings will be pretty much 3-4 years.
I already signed up to open roads fuel-saving card.
I have a standard 8 ft truck bed with a goose neck, so I have plenty of space.
What are your thoughts?
Thank you

 

[Joe Hogan]

In my opinion, unless you know your travels will require spare fuel, managing an aftermarket tank of fuel is an unnecessary headache.
If a trip is worrying you, buy a couple 5gal tanks and see if you need the extra fuel.
Once off highway, local Cheap diesel can be found with apps like Gas Buddy, etc.
a 300 Mile trip radius covers a lot of territory.

 

[Bigblockyeti]

A few more details. Where are you starting from, where are you planning on heading, how much saving have you seen where you've been buying diesel? As Joe mentioned, a couple 5-6 gallon cans initially might be worth considering unless you're positive this is an essential. 90 gallons of diesel plus a not too light auxiliary tank will put a dent in payload capacity too.

 

[Diesel Pusher]

I had a 35 gallon auxiliary tank between the frame rails on my truck which I could use with the flip of a switch, it worked well for long distance driving. The extra weight (over 600 lbs) of a full 90 gallon tank in the box plus the weight of the tank might be a concern.

 

[mjeds]

not sure what year your GMC is, but there are replacement tanks for GMCs up to 2021 models that replace the 36-gallon tank with a 50–60-gallon tank, that bolts up the OEM location, and use the OEM wiring, pumps, etc.

IMO a far better solution than a bed tank. not 90 gallons, but near doubling of your fuel supply so near double the miles

Titan 60 Gallon Fuel Tank for 2020-2021 GM 2500 & 3500 Crew Cab, Long Bed

Titan 60 Gallon Fuel Tank for 2020-2021 GM 2500 & 3500 Crew Cab, Long Bed

norcaldieselperformance.com

Fuel Tank For 2020-2025 GM Silverado/Sierra 2500HD/3500HD 6.6 L5P Duramax | XDP

Increase the fuel capacity and range in your 2020-2025 Chevy Silverado or GMC Sierra 2500HD/3500HD with a larger fuel tank. XDP is your one-stop diesel shop.

www.xtremediesel.com

 

[star1k]

In my opinion, unless you know your travels will require spare fuel, managing an aftermarket tank of fuel is an unnecessary headache.
If a trip is worrying you, buy a couple 5gal tanks and see if you need the extra fuel.
Once off highway, local Cheap diesel can be found with apps like Gas Buddy, etc.
a 300 Mile trip radius covers a lot of territory.

Thank you for your reply. Yes i do use GasBuddy and I also have Open Roads fuel card to save some. Yesterday I had to fill up in NY state ( my home state ) at $4.7 per gallon, compared to 3.5 that I filled up today in NJ. Apps did not show any gas stations in 50-miles radius ( updated prices, since I was in Catskill region )

 

[star1k]

A few more details. Where are you starting from, where are you planning on heading, how much saving have you seen where you've been buying diesel? As Joe mentioned, a couple 5-6 gallon cans initially might be worth considering unless you're positive this is an essential. 90 gallons of diesel plus a not too light auxiliary tank will put a dent in payload capacity too.

We are planning a road trip starting in NY, then going to the Florida Keys, then going to California then Colorado mountains and some other snowboarding destinations, and then back to NY. Price spread between NY and NJ close to a dollar per gallon, but for the most parts, 20-50 cents can be realistically saved.
Yes I will be adding close to 700 lbs to my truck. My payload capacity little more than 5000lbs and my tongue weight ~3200, so i still have some room. meaning it is doable with my set up. I am not 100 % sure if is essential, that is why i am asking this question to see all pros and cons for my "wants"

 

[Joe Hogan]

The beauty of the larger replacement tank is you do not need additional fuel management nor lose any space in the bed. Partial fill when you do not want/need to carry the extra weight of fuel and always have a reasonably accurate fuel gauge. Down side is the unrecoverable investment.

 

[star1k]

not sure what year your GMC is, but there are replacement tanks for GMCs up to 2021 models that replace the 36-gallon tank with a 50–60-gallon tank, that bolts up the OEM location, and use the OEM wiring, pumps, etc.

IMO a far better solution than a bed tank. not 90 gallons, but near doubling of your fuel supply so near double the miles

Titan 60 Gallon Fuel Tank for 2020-2021 GM 2500 & 3500 Crew Cab, Long Bed

Titan 60 Gallon Fuel Tank for 2020-2021 GM 2500 & 3500 Crew Cab, Long Bed

norcaldieselperformance.com

Fuel Tank For 2020-2025 GM Silverado/Sierra 2500HD/3500HD 6.6 L5P Duramax | XDP

Increase the fuel capacity and range in your 2020-2025 Chevy Silverado or GMC Sierra 2500HD/3500HD with a larger fuel tank. XDP is your one-stop diesel shop.

www.xtremediesel.com

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Thank you for this post. Yes, I did see those. My GMC is 2024, so still under warranty, which also means that i can not really go with that tank, as dealers will not install it Additionally cost for those tanks close to 2k + labor which gives me only 30 gallons of additional fuel for that money, I also seen aux fuel tank that goes into the spare tire area which will give me the same fuel capacity and it costs about the same.
RDS fuel tanks with pumps cost about the same too
So all options +/- equal in $$$ figures ( smells like conspiracy ) LOL
Yes ideally I do not want to use up bed space since I might be putting a camper in there, but the idea of not buying diesel in CA little stronger.

 

[star1k]

The beauty of the larger replacement tank is you do not need additional fuel management nor loose any space in the bed. Partial fill when you do not want/need to carry the extra weight of fuel and always have a reasonably accurate fuel gauge. Down side is the unrecoverable investment.

good points. Thank you. In my case dealer will not install it, and my car is under warranty. I was looking at options of having a tank with 8gpm pump and manually adding fuel when needed - so this way if there will be some problems with the engine dealer can not say "Sorry buddy but by cutting the fuel filling hose you voided your warranty and repairs will cost you $$$$"