How to tell how much. Oil is left in tank

GeneA1957

I have 2-275 vertical oil tanks with the fuel gauge on one tank that is just below 1/4. How much total fuel would I have left in both tanks. 

Is the gauge only reading the total fuel for one tank. 

bburd

If the tanks are piped together, the single gauge should read the level in both tanks together; so you have approximately 1/4 of 550, or 137 gallons in total.

Keep in mind that there is usually some unusable sludge, water etc. at the very bottom of oil tanks.

STEVEusaPA

If the tanks are connected at the bottom, the gauge is reading for both, unless there's a restriction in the pipe at the bottom-then you can't say for sure.
I'll assume the tanks are also connected at the top and one fill, IOW the first tank has to fill completely before the fuel flows thru the crossover in the second tank where the gauge is located? If so, NEVER put a gauge on that first tank.

EBEBRATT-Ed

Take a spare plug out of the top of the tank. Put an old ruler down into the tank and get the oil level reading in inches.

Then Google "275 Gallo oil tank chart" there are a million of them on line to convert the " to gallons"

If you have only one tank gauge with two tanks tied together the oil level should be the same in both tanks unless the crossover pipe at the bottom is plugged. The only way to know that is to measure the oil level in both tanks.

A tank gauge usually does not read in gallons. It only gives you an approximate reading of 1/4 full, 1/2 full etc.

If your system is working correctly and the gauge reads 1/4 full then both tanks should be 1/4 full.