Mackin is right on with the definiton of Cetane. He occasionally hits the mark. [img]tongue.gif[/img]
But, number one is not premium diesel. There are typically two types of diesel that you will find at the pumps. Number two (also called home heating oil), and number one (kerosene). Red diesel is the same as regular diesel except that the road tax hasn't been charged on it. Hence the reason it is called off-road diesel. It comes from the same tap at the refinery as regular diesel does. Don't get caught using red diesel on the road. The fines can be upwards of $10,000 plus $1000 per gallon of fuel capacity. But I digress.
Number two diesel has more energy than number one but has a tendancy to gel below 20*F (I think. Mackin?). Number one has less energy but doesn't gel until below -40*F (Again, I think.).
Winterized fuel is made one of two ways. By blending number two with number one. The proportion determines the gelling point of the fuel. Obviously, the more number one, the lower the gelling point. But the worse your performance will become. The other way is to have straight number two mixed with an anti-gel additive at the pump (bulk tank). This fuel has all the energy of number two (or most of it) but has a lower gelling point. Premium is number two with a cetane booster added to it. That's all it is.
So your best bet to find out what is in the tank is to ask the guy filling the tank. Usually, if you ask the person behind the counter what type of fuel they have, you will get a blank stare followed by either "I need to talk to my manager (who probably doesn't know either).", or "We have diesel?"
As for additives, I recommend using one at every fill. Most good additves have an anti-gel additive, cetane boost, lubricant additive, etc. The additives that will damage are the line driers because they use alcohol. However, most engine manufacturers recommend using this type of additive to remove water in a fuel system. But prolonged useage can (and probably will) cause damage to your fuel system. If you stay away from fuel system driers, and just use the regular additives, you should be fine. Just an FYI, my manual also says not to use it, but I feel that with the advent of low sulfer fuels, and the cold climate I live in, the added protection is worthwhile. And tell you what, I doubt it will hurt your truck. I won't recommend one over another, but I will tell you that I use Power-Service. Mainly because it's everywhere.
Does that answer your question adequately?
(Mackin, will you hire yourself out as a speel chcker?)
\'99 2500 ISB QC SLT (No Leather!),4x4,5sp w/McLeod,4:10,BP8x11\'s,B-1,FMS,EZ,PE4200,LPG,H2O/CH4O,4\"exh.,Pac-Brake,OBA,more switches than you,Line-X,V-1,lts,siren,lic. plt. frm says \"<b><i>Diesel Fumes Make Me Horny!</i></b>\",and much more goofy stuff.