We began having problems with surges & hesitations shortly after filling our tank at the local station. We called the station and the owner tested the station tank. Nothing showed up. The next day the problem with our car continued and the check engine light came on. We took the car into the dealership and their testing said we needed to replace the fuel pump. We later found out that there was water in the station tank and thus in our car tank. My question is: can water in the fuel tank ruin a fuel pump?
Yes, and any dealer or shop who tells you that water is involved should be prepared to take a sample of at least a quart and keep it for your inspection.
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Tell the fuel station of your complaint. Tell the fuel SUPPLIER of your complaint.
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Fuel pumps are designed to pump liquid, and gasoline is not much different than water. I once had a vehicle into which a large amount (many gallons) of water was pumped. The mechanic disconnected the fuel line and used the vehicle’s fuel pump to empty the gas tank.
The engine ran poorly for about a week until the last bits of water made their way through the system, but there was no permanent damage and the fuel pump continued to function normally.
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Can water ruin a fuel pump? Maybe. I’m skeptical. As you are probably aware, air slips into the tank as you burn off fuel and that air can contain a fair amount of water vapor – especially in humid climates. The water then condenses on the cold walls of the tank at night and ends up at the bottom of the fuel tank where it is sucked up by the fuel pump, mixed with the gasoline and burned harmlessly. (Some of it dissolves in the gasoline and is burned that way)
Folks in cold climates frequently dump a pint of isopropyl alcohol into their gas tanks in the late fall to help dissolve and get rid of the Summer’s accumulation of water in the tank before it freezes and causes trouble. Fuel pumps have to be designed to deal with the worst cases of water accumulation in the fuel tank. And Toyota tends to build their vehicles like tanks. Their fuel pump probably will not be flimsy.
So, maybe the fuel pump is damaged. And maybe it isn’t. You should at least hold open the possibility that the folks at the dealership don’t know what they are talking about.
You can either have the fuel pump replaced which may not be outrageously expensive. On many Japanese cars, the fuel pump is quite accessible and can be replaced without dropping the fuel tank. Or you can get a second opinion from a good independent mechanic. Or you can do your own checks if you have some basic tools, some time, and the inclination.
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Reference the old cold weather practice of adding isopropyl alcohol or “dry gas” to the tank to soak up water. Now that almost all gas contains at least 10% ethanol in the winter months, is there any need to continue the old dry gas treatments?
The tanks would have to be leaking for this to occur. Ethanol should make water content a thing of the past.
I too don’t see why a fuel pump would fail with water while not with a solvent like volatile. Fuel has no lubrication qualities.
Now if it’s fouled with stuff contained in the water, that’s another story, but the sock and the mesh that’s on the inlet of the pump should protect it.
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Don’t PANIC !!!
I just poured antifreeze in my gas tank and it stalled before I realized I used the wrong gas can. I obviously shut off the engine, opened all the gas lines, and emptied the tank. I let everything sit overnight, I refilled the tank with 93 octane and after about three starts, the engine turned over with no problems. I let it run for a bit and put in some Seafoam. Crisis averted…! Fuel pumps are used to move fluid - just because you put in water or antifreeze should not destroy anything if you catch it in time and purge all the bad stuff out. Good luck.
You had antifreeze in a gas can ? Why ? Also this person asked their question 9 years ago.
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After doing a lot of research, and I mean A LOT!! I did testing on antifreeze in gas in 27 countries on 5 continents, summer and winter. After I finished my research 3 years later and got home to analyze the info, I realized I left the notebook with the info in Switzerland on a bus bench. All I could imagine was some long hair sissy boy wacking off to the info in my folder 
So I started over with all the research, I cut it short and only repeated the data in 18 countries both summer and winter.
What I came up with is, as long as you get the antifreeze or water out of the tank before it does damage, you will be alright pal.
You are welcome.
Only 14 years too late.
story of my life
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