Actually my advice would be to not drain it unless you suspect it is contaminated. Diesel fuel can easily last 3 years without significant degradation. If it was stored someplace very warm you might have fungus in it though. If you do decide to drain it you can remove the tank screen at the bottom of the tank and clean it out too which is a good thing to do.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz