Cleaning the tank afterwards is about the same for all these options. If
you fill it with water getting the vast majority of the water out is easy,
just syphon it out. It the last remaining water or whatever that is
trouble. I take the fuel gauge sender off so I can put a syphon all the way
to the bottom. Most pickups do not go to the bottom so that whatever water
or crud accumulates will not get picked up.

"DSK" wrote in message
...
JamesgangNC wrote:
Actually filling a tank with water is a comon way to test for leaks.
Particularly with large tanks where filling the tank with fuel can be
costly
and dangerous. It's not like a large fuel tank doesn't get a little
water
in it from time to time.

That last point is true, but that doesn't make it a good idea to
deliberately fill the tank with large amounts of water.

Frankly, if filling a tank with water is so common, how come there is no
mention of it whatever in either standards or in contractors handbook?
It seems to me that cleaning the tank afterwards would be more trouble.

Gene's phenolpthalein test is a lot more common in my experience,
although I haven't seen it done with large tanks which are usually air
tested after scrupulously gas freeing them.

Fair Skies
Doug King