Can water in gasoline ruin a fuel pump?



I have a 1997 Saab 900S. It wouldn’t start this morning. The engine turns over, but it won’t catch and run. The same thing happened 10 weeks ago, and the garage put a fuel pump in it. They’ve just told me it needs another fuel pump - that there was a gallon of water in the bottom of the tank, and the water ruined the pump. They asked if I always go to the same gas station, which I do about 80% of the time, and said the problem is probably bad gas. In the 2 years I’ve had this car, it has never run poorly. Except for these 2 occurrences, it has always started immediately, and there’s never been any hesitation, coughing, spluttering, whatever. Shouldn’t there have been symptoms of water in the gas long before it got so bad that the fuel pump died? Please help!


I think they are handing you a load of baloney. With a gallon of water in your tank (even a quart) you would not have been able to make it home. And water should not destroy a fuel pump; they work on all sorts of liquids.

“Bad gas” gets the blame for everything. But what is actually going on with your car, that I cannot say.


I’d suspect a bad pump which should be under warranty or the connection or wiring to it. I had a bad pump and the GM replacement was bad right out of the box. The next GM pump lasted a month and was replaced a no charge. They should cover at least the part.


How does WATER ruin a pump?? It’s a liquid. Maybe after a couple of years the water would eventually promote rust in the pump…but to ruin it in 10 weeks…They’re just NOT standing behind their work. I’d DEMAND that they fix it. And after they do…NEVER go back there…unless the pump fails again.


I would take your car to another shop and have it looked at. There are other things that can go wrong and cause the same problem. I suspect it could be a relay or bad connection somewheres to the fuel system. It could even be in the ignition system.

By chance was there any CEL (Check Engine Light) before it quit running?


Can they explain how the water got into the tank?

I would suspect they didn’t install the new pump properly and that’s how water got into the tank in the first place. So they need to fix this at no charge to you. Plus water is not going to cause a fuel pump failure.


For you to get an idea of how a fuel pump problem is diagnosed, replaced, and the fuel tank cleaned during this task, go to:


I’m going to veer off here a bit. Water in the gas is often an excuse if someone does not know what the problem is.

However, water in the gas CAN occur and yes, water can ruin a fuel pump. Pour water into a pop-up toaster and what happens? End of toaster.

A car (2 years old)was towed in to us not once, not twice, but THREE times from filling up at the same station (Texaco); and all within a 1 and 1/2 month period.
One would think the first go-around would have been enough.

The water that was in the tank (better than a gallon from best estimates) was so clean that one could swear that it was potable water.
A full quart container of this was saved just as it drained to show the customer, and if this is legitimately the problem with your car the shop should also save a healthy sample.

Ask to see a sample and see what happens.