I installed a 52 gallon Titan tank in my 2022 diesel 2500 Crew cab short-bed March of this year (2022). I love the extended range of the tank but my tank leaks too. I looked under my truck back in the summer and noticed the bottom of the tank was wet with diesel fuel but was not actively dripping… it was just wet. About two months ago one day after filling the tank and parking the truck in my driveway, I noticed a constant drip from under the tank. Ugg…. I put a pan under the drip. By the next morning almost a quart of diesel had dripped out into the pan. I slid under the truck with a flashlight to take a closer look. The diesel was dripping from the small air intake one-way check valve clamped on the very top of the tank by a 3” long tube.
The small (approximately 1/2” x 1”) one-way plastic (nylon?) check valve lets make-up air enter the tank as the fuel is used. (I guess this is its purpose.) That check valve is suppose to only let air in and certainly no fuel out. My valve is obviously broken or has trash in it, keeping it open. Because the valve is located on the top, I discovered that the valve leaks only when I fill the tank up ‘’all the way”. I found that when filling my tank, and the pump filler nozzle auto-clicks off, I can hear the tank gurgling as the fuel settles/equalizes into the tank. I suppose fuel is moving across the top of the tank filling the various (compartments) and equalizing. I can again run fuel into the tank allowing the filler nozzle to click off and will do this about 4 times. I can get another 2-4 gallons into the tank this way… topping it off. Well when I do this, the fuel level I suppose gets above that air intake check valve and so that topped-off fuel leaks down through the stuck-open valve.
My immediate fix is to not top off the tank. After the fuel pump nozzle clicks (auto-cuts off) once, I stop adding fuel. I have not had a leak since I stopped topping off the tank. My long term fix is to install a new (and better, see Summit racing) fuel tank air intake valve, and to change it’s location. As delivered the valve is connected to the tank by a short 3” tube and the valve lays horizontally on top of the tank. I will change that short tube to a longer 18-20” tube and nylon tie the valve up high on the tank’s filler hose. So in the future when I top off the tank, that air check valve will hopefully be above the fuel level… just in case the air valve sticks open again.
