garyculb18
Member
- Oct 18, 2025
- 60
- 36
- 18
Larger Gas Tank for the Lexus 700h
After 9K miles I just could not take it anymore.
Traveling at least 70 miles a day 5 days a week I had to get a bigger gas tank for my 2025 700h LX F-Sport. Could not put the SUV in Econ or Comfort to improve gas milage because of the awful pitching/wobbling/bouncing that occurs on bumpy roads. So, I only get around 16-18 mpg. Whoever decided at Lexus that the $125,000 700h LX should have a 17.9 gallon gas tank should be let go.
There was only one manufacture, FK Industries in China, that in 2/26 made a larger gas tank for the 700h LX (110 liter or 29 gallons: (https://fkoffroad.com/products/longrange-main-fuel-tank-fit-for-lexus-lx700h?variant=51911369031998 ). They also make an auxiliary tank but, installation looked a bit more complicated (https://fkoffroad.com/products/fk-long-ranger-fuel-tank-lexus-lx700h?variant=51705972064574 )
The company has a great video on installation of both tanks:
I went to the shop foreman, Ryan, at my Lexus Dealer, Jim Hudson Lexus in Columbia, SC and discussed the larger tank install. The Dealership agreed to install a large gas tank on my 700h LX and allow me to keep my 100K mile extended warranty. $1,775 (including shipping) & item arrived from China in 2 months. FK shipped the new gas tank in a wooden box. It arrived without an issue directly to my Lexus Dealer.
Jim Hudson Lexus gave me an RX loaner while they did the install. The Lexus shop foreman, Ryan, stated that installation was Plug & Play, not complicated and no error codes occurred. He filled up the new tank & saved the old one for me to take home. Dealer Charge was $988.
Down Side: The miles on the fuel gage do not match the actual milage you can drive /gowith the larger gas tank. It takes allot longer to get down to 1/4 of a tank. I have been waiting until the reserve light comes on before I stop to fill up.
From FK Industries:“With the increased capacity of our tank, a larger fuel reserve remains when the warning light activates. Drivers can expect approximately 100 km/62 miles of additional driving range after the low-fuel indicator illuminates, allowing ample time to refuel with confidence.”
OMG what a difference!
Having an extra 160 miles of travel will be fantastic. Yes, that is a total driving range of 420 miles for me! The increase of approximately 70 lbs on the left side of the vehicle is not noticeable. The SUV has handled the same after the install. Now, I only have to fill up once a week! 
Just had installed so will update in about a month or two.
Again, whoever decided at Lexus that the $125,000 700h LX should have a 17.9 gallon gas tank should be let go.
Highly Recommend!!
Best,
Doc
After 9K miles I just could not take it anymore.
Traveling at least 70 miles a day 5 days a week I had to get a bigger gas tank for my 2025 700h LX F-Sport. Could not put the SUV in Econ or Comfort to improve gas milage because of the awful pitching/wobbling/bouncing that occurs on bumpy roads. So, I only get around 16-18 mpg. Whoever decided at Lexus that the $125,000 700h LX should have a 17.9 gallon gas tank should be let go.There was only one manufacture, FK Industries in China, that in 2/26 made a larger gas tank for the 700h LX (110 liter or 29 gallons: (https://fkoffroad.com/products/longrange-main-fuel-tank-fit-for-lexus-lx700h?variant=51911369031998 ). They also make an auxiliary tank but, installation looked a bit more complicated (https://fkoffroad.com/products/fk-long-ranger-fuel-tank-lexus-lx700h?variant=51705972064574 )
The company has a great video on installation of both tanks:
I went to the shop foreman, Ryan, at my Lexus Dealer, Jim Hudson Lexus in Columbia, SC and discussed the larger tank install. The Dealership agreed to install a large gas tank on my 700h LX and allow me to keep my 100K mile extended warranty. $1,775 (including shipping) & item arrived from China in 2 months. FK shipped the new gas tank in a wooden box. It arrived without an issue directly to my Lexus Dealer.
Jim Hudson Lexus gave me an RX loaner while they did the install. The Lexus shop foreman, Ryan, stated that installation was Plug & Play, not complicated and no error codes occurred. He filled up the new tank & saved the old one for me to take home. Dealer Charge was $988.
Down Side: The miles on the fuel gage do not match the actual milage you can drive /gowith the larger gas tank. It takes allot longer to get down to 1/4 of a tank. I have been waiting until the reserve light comes on before I stop to fill up.
From FK Industries:“With the increased capacity of our tank, a larger fuel reserve remains when the warning light activates. Drivers can expect approximately 100 km/62 miles of additional driving range after the low-fuel indicator illuminates, allowing ample time to refuel with confidence.”
OMG what a difference!
Having an extra 160 miles of travel will be fantastic. Yes, that is a total driving range of 420 miles for me! The increase of approximately 70 lbs on the left side of the vehicle is not noticeable. The SUV has handled the same after the install. Now, I only have to fill up once a week! Just had installed so will update in about a month or two.Again, whoever decided at Lexus that the $125,000 700h LX should have a 17.9 gallon gas tank should be let go.
Highly Recommend!!
Best,
Doc
