Gas Tanks Question
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Joined: Dec 2024
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From: Lancaster, KY
Gas Tanks Question
Sorry if this has been asked before, but I have a question about how the gas is allocated between the left and right tanks. Is the left tank used first and then the right tank siphoned over to the left tank? If so, does this mean if you always fill up when your gauge is at 1/2, does the right tank gas not get used (goes stale)?
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Joined: Dec 2024
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From: Lancaster, KY
So the right tank siphons over as the left tank is supplying the engine. In-other-words, always filling up at 1/2 tank will not result in stale gas in the right tank because it was not being used?
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Well, you add fresh gas whenever needed, so
its always mixing and circulating… how would it get stale?
when the left tank fills, the main crossover tube at the top of the tanks spills new gas over into the right tank, mixing new gas in.
as the car is running, the pump in the left creates more fuel flow and pressure than the engine needs, and the excess is directed to the right tank by a small crossover tube, which drives the siphon, pulling gas into the left tank through yet another small crossover tube. So gas is always mixing and moving, but the left tank is favored. These two tubes run inside the large top crossover tube.
its always mixing and circulating… how would it get stale?
when the left tank fills, the main crossover tube at the top of the tanks spills new gas over into the right tank, mixing new gas in.
as the car is running, the pump in the left creates more fuel flow and pressure than the engine needs, and the excess is directed to the right tank by a small crossover tube, which drives the siphon, pulling gas into the left tank through yet another small crossover tube. So gas is always mixing and moving, but the left tank is favored. These two tubes run inside the large top crossover tube.
Last edited by Gorn Captain; May 30, 2026 at 04:57 AM.
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From: Texas
Correct. C5 fuel filters are also the fuel pressure regulator (forward regulated). Left tank has the pump and feeds the filter with excess/bypass fuel fed to the right tank. This also drives the siphon/crossover tube via "jet pump" in the right tank. Both tanks are constantly mixing when the fuel pump is running.
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Joined: Dec 2024
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From: Lancaster, KY
......as the car is running, the pump in the left creates more fuel flow and pressure than the engine needs, and the excess is directed to the right tank by a small crossover tube, which drives the siphon, pulling gas into the left tank through yet another small crossover tube. So gas is always mixing and moving, but the left tank is favored. These two tubes run inside the large top crossover tube.
