"Duane Bozarth" wrote in message
...
wrote:

...
I have never heard of an oil tank getting thin unless it's in a real
wet basement and rusted severely. ...

I wouldn't say "never" but it certainly should last the proverbial "long
time". Of course, the prime location they rust is from inside out from
condensation moisture collected over the years. How much of an issue
that is depends also to large extent on how wet the locale/installation
is and whether there is a water trap installed.

I disagree. This is an oil tank. If condensation did collect on the
inside, the oily coating would work to prevent rust*. It possibly could
happen (especially if oil never contacts the topmost portions of the tank
interior) but I doubt it is the prime location (components of oil probably
vaporize and condense more readily than water in the same vessel)
furthermore, there is likely to be an oxygen depleted atmosphere in the tank
further inhibiting rust. On tanks containing other liquids maybe
(especially compressor air tanks) but not an oil tank. Tools are often
coated with oil to prevent rust during storage or shipping as an example
(different oil but similar effect).

I would expect condensation on the outside of a tank full of cool oil
sitting in a warm damp basement during humid summer days (like a half full
cold can of soda on the table). Rust would be particularly evident on the
bottom where any formed water droplets would migrate.

If you do see rust, don't use a wire brush to clean it off. Use a rust
inhibitor paint that will chemically convert the rust and cover it up. You
don't need pretty, just functional.

The insurance caveat does give real reason to consider replacement though.
I would wait for the first pinhole leak then patch first, it's unlikly the
tank would suddenly burst open anyway.

*(my reasoned opinion not from experience with oil tanks)