How long will diesel keep for

It should keep for years if not contaminated.

Damien

I keep 3000L of spare diesel on hand here in 1000L pods (Plastic container in a pallet size steel crate)

We use it as a reserve for our bowser as our underground tank is only 11000L and sometimes has trouble lasting between tankers.

Our fuel supplier advised that it should be good for 12 months before it starts degrading, I usually change it every six months.

Dru

Ensure your tank is clean.
Fill with clean diesel.
Add some chemtec, or nulon diesel treatment as per dose on bottle instructions.
If kept sealed will be fine for years.

Couple of things happen do diesel.
If there is water present, there is a chance of alge growth at the line of water/ diesel.
Diesel bugs feed on the sulphur, so in essence the low sulphur fuel can keep for longer.

Diesel can over time become cloudy with particulate.
Inspect ,and filter as required.
Your good to go.
I also add in 200:1 ratio some 2t 2 stroke oil for extra lubricity.

You can also use fuel stabilisers for long term storage.

Keep fuel out of extrem heat and sunlight, ensure containers are sealed, and your good to go.

Trains

Ps, winter grade diesel has a lower wax point, so if storing for long time, store winter grade as you can use it in either winter or summer.