First, to give you some info, I have been making bio for 18 months and running it in my 03 Jetta TDI, 05 Passat TDI, as well as 83 Dodge Ram. Passes 3/27, washed until water is clear and dried under heater/fan. Then, I run my bio through several micron filters and have a Goldenrod water filter and fuel filter on my gas pump. So far, all is great with the VW's and Ram. 03 Jetta has 30,000+ on B100; 20,000 on Passat.

Now, we just purchased a 2005 GMC Sierra Duramax with 12,000 miles on engine. I have read about DPF issues and I might need to disconnet. I AM NOT mechanically inclined--basic oil change and air in my tires. We can change fuel filters if my bio brings up junk from the fuel tank, but with such low miles, may not see anything.

Can anyone give me info on what I can expect from the Duramax? I have run B50 in the first tank, but would like to eventually get to B100 by the summer. If I run into any major problems with Duramax and bio I will have to get a professional to fix it, and of course when I went to the GMC dealership, they smelled the bio and lectured me on ruining my engine. My VW dealership approves of my bio use, and even has a diesel mechanic who makes and drives it as well. I was also told that my bio will have to be perfect--high conversion and 0 methanol and soap or I could see problems. I plan on making quality fuel.

Your truck should run better.You may need a chip,I would.I smoked a 2009 with my SD.

The 2005 does not have a DPF on it, these came out on the 2007 models. I have a 2004 duramax and have put 68,000 miles on it with 100% bio. (It has a total of 108,000 miles on it) I have not made any modifications to the truck.

Glad to hear that the 05 won't need any modifications. I appreciate the info from both of you. I probably won't be adding a chip, since I have no idea what that means. It's good to hear diesel4me that you have had no problems and needed no mods. I tried to research and it seemed that if I stayed with an 05 or older, that people who posts on various forums weren't have any problems running quality fuel. Can I go straight to B100 or should there be a "break in" process? I bought this truck with the plans to run 100. Also, I have read I can expect a small difference in towing power.