Are any diesel fuel conditioners needed or would be good to use on Subcompact tractors, about 21 hp. Mines new LS122 and mostly sits. It works a few hours a week? Tks
The new low sulfur diesel fuel lacks lubricity. Sulfur was a good lubricant.
Older diesel engines were never designed to run on today's low sulfur fuel (that is engines designed early 2000 or before). Hence it is a good idea to add the lubricity back to our diesel fuel for older engines. This can be done by adding a small amount of two stroke oil, at a rate of about 1:200 to 1:300. The very cheapest mineral oil based two stroke oil is perfect for this purpose, no need to spend money on expensive synthetic two stroke oil or even more expensive additives. It only has to lubricate the pump and injectors, nothing else. And it should burn just like diesel fuel does, without adding any extra carbon residue (as it does in two stroke gas engines).
If your engine is a modern design, say designed (not manufactured) after about 2005, it should be designed to run perfectly fine on low sulfur diesel, and the pump may be separately lubricated by engine oil, not just by the fuel itself. It does not need any extra lubricity additives whatsoever.
Now, my tractor drives less than the car. It only does about 60h a year. And I store it's diesel in a dozen jerrycans, enough for about one year. So I also add some diesel stabilizer to keep it fresh and avoid bacteria growth. I use the same treatment that the petrol companies already add to diesel, they just use it in smaller quantities as fuel it is intended to be used right away, not stored for a year as I do. It's called Pri-D fuel stabilizer, and sold by Amazon.
Warning: in the old days, people used to add gas (we call it petrol in Australia, its what goes in normal cars that do not have diesel engine) to diesel in winter to prevent it galling in the cold. That is a very bad idea today, as some gas (aka petrol in AU) nowdays contains ethanol, and you can never be 100% sure if it does or not no matter what the label at the pump station says. Ethanol absorbs water from the air and keeps it in solution instead of separating it out at the bottom of the fuel filter, and you end up with rust inside the old style (not common rail) diesel injectors and pumps that are made of plain steel.
