Water In The Gas Tank?

[Marc 2019 RST]

So, when the fuel level on my '19 RST/Z71 gets low enough to cause the alert to pop on, I also begin to get a slight shudder/vibration in the engine. Dealer tech say "no problem found", even when they do notice the shudder and how it is fixed. Supporting my theory of water in the tank is when more fuel is added, it takes a couple seconds for the shudder to stop. I think this is the fuel line clearing and then siphoning in fresh fuel that contains no water since it above where the water exists in the tank.

If I am correct and it is a water problem, will this harm the engine? If not, is there a fuel pump issue that exists when the tank gets low enough?

I fly small single-engine aircraft; for small aircraft like single-engine Cessnas and Pipers, the pre-flight check-list requires attention to the fuel tanks where water can collect at the bottom and is removed using a tool and a special valve in the wing to capture the water. No such deal with my Tahoe, however, the quick fix is to simply add gas and the shudder goes away.

Advice???
Thx,
Marc

 

[Fless]

If you can find a way to sample your fuel when it's doing it, take a sample in a clear container and let it sit for a few minutes. The water will go to the bottom and you'll be able to see the line between the water and the fuel. Similar to testing for ethanol content, but without adding water to the container.

 

[Vladimir2306]

In summer, nothing will happen to the engine, and in winter, the water will freeze in the mains. But water is heavier than fuel. And it is always at the bottom, and the fuel intake from the tank comes from the lowest point. Therefore, water goes into the engine first and cannot be collected there in large quantities. But if there is a concern, then you can pour 1 liter of etanol, it will dissolve water in itself. Or a special fuel attachment to remove water

 

[Mean_Green]

Does anybody use SeaFoam, Marvel Mystery Oil or other additives/driers in these vehicles? I use it in all my yard machines. In my Sebring, i was told to use Techron about every third tank.

 

[Doubeleive]

mmmm, not sure how you would end up with water in the tank, but what I would do is verify the float is working properly and that you are not getting so low on fuel that it can't maintain a steady flow. my 03 silverado was notorious for giving me a warning shudder when the fuel got to 1/4 tank or less if I didn't find a gas station in short order I was going to run out even if it still showed a 1/4 tank it was WRONG.
for me changing the pump with a brand new one made no difference it was just the way it was
I ran my 18 silverado out of gas a couple months ago, no warning at all other than "hey dummy low fuel" it just straight up died on the freeway, luckily I actually managed to coast about a 1/4 mile and down a offramp right into a open spot at a gas station. lol couldn't have happened any better.

 

[Mean_Green]

^^^^ I did almost the exact same thing on the down end of the Eisenhower Tunnel coasting into a station at Silverthorne. That was in a Ford Ranger PU.

 

[B-train]

mmmm, not sure how you would end up with water in the tank, but what I would do is verify the float is working properly and that you are not getting so low on fuel that it can't maintain a steady flow. my 03 silverado was notorious for giving me a warning shudder when the fuel got to 1/4 tank or less if I didn't find a gas station in short order I was going to run out even if it still showed a 1/4 tank it was WRONG.
for me changing the pump with a brand new one made no difference it was just the way it was
I ran my 18 silverado out of gas a couple months ago, no warning at all other than "hey dummy low fuel" it just straight up died on the freeway, luckily I actually managed to coast about a 1/4 mile and down a offramp right into a open spot at a gas station. lol couldn't have happened any better.

Been there. Had a 2003 yukon that the low fuel light came on just below 1/4 tank. About 2 miles later I coasted as far as I could, then luckily had a coworker close by that gave me a lift for gas. I now rarely go below 1/4 tank. (My wife seems to have luck in doing so, to my dismay).

I did try the low fuel on my work truck just to see the accuracy and I'd say it's pretty close to what should be left. When the Ford says 25 miles left, it's pretty accurate and I know I have about 40 miles of range, but no interest in finding out on the side of Hwy 90.

 

[Doubeleive]

Been there. Had a 2003 yukon that the low fuel light came on just below 1/4 tank. About 2 miles later I coasted as far as I could, then luckily had a coworker close by that gave me a lift for gas. I now rarely go below 1/4 tank. (My wife seems to have luck in doing so, to my dismay).

I did try the low fuel on my work truck just to see the accuracy and I'd say it's pretty close to what should be left. When the Ford says 25 miles left, it's pretty accurate and I know I have about 40 miles of range, but no interest in finding out on the side of Hwy 90.

My 18 will show how many miles remaining until it gets to around 20 miles then it just says low fuel, I figured I could have made it to the next exit which was what I was shooting for but I have a heavy foot so I think once it had dropped under 20 earlier in the day I had done a few wot and pretty much reduced that 20 to 5 lol.
so now when it say's low fuel and no miles I take it for granted it's time to find gas
gas here is still over $4 a gallon but there are a couple stations that are cheaper than the rest if you use cash, I tired to get there, with my 03 you could hit brake/gas a couple times and it would make it a little further but no such luck with the 18

 

[Marc 2019 RST]

If you can find a way to sample your fuel when it's doing it, take a sample in a clear container and let it sit for a few minutes. The water will go to the bottom and you'll be able to see the line between the water and the fuel. Similar to testing for ethanol content, but without adding water to the container.

 

[Marc 2019 RST]

Thx! Will try to figure out a way......am sure it must be water in there somehow.
Regards,
Marc