I'm a diesel novice. Jut purchased a 2003 GMC 2500 Duramax/Allison and I've read about people using additives and upgraded fuel filters. Are these really necessary, or are they being overly cautious? What do the additives do? Where do you get the additives and the filters? I've heard that you add something in the winter to keep it from jelling, but what are you guys putting in during the summer? Also, I live in Indiana and it gets well below zero some times. Do you still have to plug diesels in to keep them warm overnight? I've looked around in my engine compartment and can't seem to find a block heater anywhere. If I have one, where is it? Thanks.

1) Secondary filtration is your choice. If you feel better with a second, finer filter, do it. Also, try to buy your fuel at truck stops or stations that sell a lot of diesel.

2) Additives can raise cetane level (like octane rating for gas). They help lubricate the fuel system and can help take water out of the system (diesel fuel is sensitive to water). They can also help keep the fuel from "jelling" in the winter.

3) You can get additives at many places. You have FPPF, Power Service, Stanadyne, and a few others. You can find these through the supporting vendors here, or you can buy at auto parts stores, truck stops, etc....
As for filters, this site started because Nick (Diesel Power) sells the "Nicktane" setup for under the frame. Racor makes a nice filter, too.

4) In our part of the country, stations switch to "winter fuel" around November. It is blended to work in colder climates. I personally have not ever had to add anything for "jelling". If your truck will sit for extended periods, or if we lived in a much-colder area (Alaska), anti-jell would be a good choice.

5) During the winter, it is a good idea to plug it in at night, if the temp is going to get down under freezing. I use a timer, and set it to come on for a couple hours before I usually leave in the morning for work. Keep in mind, though, that it's not plugged in while I'm at work, and I haven't ever had problems starting the truck when I got back after 10 hours on the job. It just takes the glow plugs a bit longer to fire up (the "wait" light) is all.
The heater plug is located attached to the wiring harness on the right side of the engine, down by the exhaust manifold near the front. You'll see a standard 120-volt plug, attached to about 6 feet of cord.


Keep in mind, this is just a quick once-over by me. Do a search around the Place for more specific answers...after 2 years, we've covered a lot of ground.

Glad to see you kept the truck. Silly fuel sender.......

Tom