Fuel Gauge Safety Margin?

How much of a safety factor is designed into fuel level gauges? This morning I pulled into the truck stop with my gauge just hitting the beginning of the red zone. In theory, that would put me at 1/8 of full. I’ve got a 200 gal capacity, but it only took 125 gals to fill the tanks. So, at 1/8 full I still had approximately 75 gallons left. But at 1/8 full, that’s technically only 25 gallons. My question is this: is that because the manufacturer builds in a safety margin? I have a Frightliner, is this the same for other manufacturers? Just curious. I get real nervous when the needle hits that red zone.

25 gallons in each tank when my low fuel light comes on. I've ran my KW down to where it took 190 gallons once. Usually though, my fuel stops will stretch it to where it's been on E and the fuel lights been on for a bit, and it will fill 150 gallons. My light comes on at 1/8.

1 time in Florida, my gauge was in the red a tad. I had to drive further for fuel, kinda wondering how much fuel I actually had ! Think I went another 200 miles for fuel. So my guess is maybe you got a good 300+ yet to go....Our tanks were 125 gal. most I ever filled up was 157 gallons near in red zone. (averaged 7.8 mpg @ 67 mph maxed)

All individual trucks are different. Do not let it get low because:

1. You're pulling all the sludge and junk out of the bottom of the tank.

2. A lower level in the tank will gell up faster in cold weather.

3. What if there was only one station at your planned exit, then suddenly there is no fuel there for whatever reason? It's now 200 miles to the next truck stop, or you must backtrack 65 miles, making your delivery late.

All individual trucks are different. Do not let it get low because:

1. You're pulling all the sludge and junk out of the bottom of the tank.

2. A lower level in the tank will gell up faster in cold weather.

3. What if there was only one station at your planned exit, then suddenly there is no fuel there for whatever reason? It's now 200 miles to the next truck stop, or you must backtrack 65 miles, making your delivery late.

Sound wisdom Mr. Jeremiah Johnson.

I really don’t like the needle to go below 1/4 tank, but once in a while it does.

Same, usually filled around 3/8 tank mark, or start looking for next stop

How much of a safety factor is designed into fuel level gauges? This morning I pulled into the truck stop with my gauge just hitting the beginning of the red zone. In theory, that would put me at 1/8 of full. I’ve got a 200 gal capacity, but it only took 125 gals to fill the tanks. So, at 1/8 full I still had approximately 75 gallons left. But at 1/8 full, that’s technically only 25 gallons. My question is this: is that because the manufacturer builds in a safety margin? I have a Frightliner, is this the same for other manufacturers? Just curious. I get real nervous when the needle hits that red zone.

I’m in a Freightliner too and had to roll 55 miles on red before and could only put 142 gallons on when I got there. I was sweating bullets but fuel and routing assured me I had enough so I assume they know the gauge isn’t very accurate.

Yeah, lots of them sitting behind a desk back at the terminal are better drivers.

SMH

Yeah, lots of them sitting behind a desk back at the terminal are better drivers.

SMH

If they gave the driver bad advice, the desk jockeys would come out to your truck with plenty of fuel, prime the fuel system and take the driver out for pizza. Wouldn’t they?

Yes, there is a safety margin built in. I've run on, "imaginary diesel" before - the needle is below the last marker on the gauge. A Volvo will go a good 1/4" into no man's land and still run fine. That said, I don't recommend this. I didn't have a choice - was told to pick up a truck another driver had abandoned and drove it to the nearest fueling point.