Fuel quality
Most stored-fuel problems come down to four things: water, microbes, cold, and time. These guides cover how to spot each one in your tank and what to do about it.
Start with what you're seeing
| What you're seeing | Where to start |
|---|---|
| Water on the gauge stick or in a sample jar | Water in your diesel tank |
| Slime on filters, or filters plugging early | Diesel bugs and biocides |
| Fuel that's been sitting for months | How long diesel lasts in storage |
| Cloudy fuel or plugged filters in cold weather | Diesel gelling |
| Getting a tank ready for winter | Winter diesel additives |
All fuel quality guides
- Water in your diesel tank
How water gets in, how to check for it with paste or a clear jar, how to get it out, and how to keep it out.
- Diesel bugs and biocides
How to spot microbial growth, test for it, and treat a tank step by step without plugging every filter.
- How long does diesel last in storage?
Shelf life, what makes fuel go bad, how to tell if it's still good, and how to make it last.
- Diesel gelling: when it happens and how to prevent it
Cloud point, CFPP, and pour point explained, why bulk tanks gel first, and a winter checklist.
- Winter diesel additives
How anti-gel works, how to treat a bulk tank before the cold, label treat rates, and when blending makes more sense.