Thanks all.
I have been using Amsoil's cold flow additive -- primarily because a case of it came with the tractor -- with only a vague understanding of issues such as the difference between "filter icing" and water contamination. I was inspired to learn more the other day when temperatures dropped below freezing and the tractor stalled within a few seconds of starting. Long story short: I had to remove the fuel tank and line and thaw out the ice plug preventing fuel flow. Replaced the filter while I was at it, although there was no ice there. Found another chunk of ice in the bottom of the treated jerry can and started researching.
That's when I learned that cold flow is a different issue and "filter icing" has nothing to do with water contamination. But, that's also when I noticed the lack of solid data behind additive manufacturer's claims. While there is a wide array of supposed brand comparisons out there on the internet, 99.9% of them seem to be repeating company advertising literature with no real independent research.
Around here, the temperature usually drops below -40° a few times each winter, so I want to make sure the fuel is protected. But I am starting to believe that cold flow improvers are only potentially useful when added to a summer grade of #2 diesel and that (as Dave suggests) there is no real room for improvement beyond what the refinery already does to produce a winter grade.
As for my original water contamination problem, I have been using a product called "Water Worm" (made by H2O Control Products in Sudbury) in my home heating oil tank for years now. It's a mechanical solution -- a long cotton sock containing a desiccant that absorbs and traps any water contamination in the fuel. I wrote them and they do make a miniature version suitable for use in the tractor's fuel tank. I think that is more suitable in a tank were the fuel line connection is off the bottom where the water collects compared to a chemical that precipitates the moisture out of the fuel. For now, I decanted the remaining fuel from the jerry can, cleaned out the ice chunk and replaced all the fuel with fresh.
As for the hydraulic fluid fire Dave came across: hydraulic fluid is typically considered combustible rather than flammable -- that is, the auto-ignition temperature is fairly high, on the order of 500° or 600°F. But that's in the reservoir; it is well documented that things change when a pressurized oil mist is sprayed out of a leak. In that case it is easily ignited in a ball of flame resembling a gasoline explosion and the film of hot oil coating everything will continue to sustain combustion. Even if you have an extinguisher, it can be difficult to extinguish, especially if it's still under pressure.
If you do experience a fire, shut the tractor off on your way out. If you have an extinguisher (class ABC dry chemical), you can try to fight it, but remember that the extinguisher will only last 30 or 40 seconds. Use the acronym P.A.S.S.:
Pull the pin.
Aim at the BASE of the fire from about 5' to 8' away
Squeeze the handle.
Sweep from side to side, coating everything with the chemical.
Aiming at the base of the fire is real important: you have to hit the thing that is burning, not the flames above it. That will be difficult on a tractor with loader arms, hoods etc. obstructing access. You are facing long odds with a small hand-held extinguisher and a big leak.
The best way to fight the fire is prevention. Inspect for leaks and potential leaks like chaffed lines regularly and replace them as necessary rather than dismissing them as minor with the thought of getting to them later. Same with wiring.
Sorry, I seem to have hopped up on a soapbox here and wandered wayyy off topic. I'll get down now...
