We don't have many options for bio around here, but will be doing some traveling this summer where it might be available. What help can you guys offer as far as what effects it's use will have? Like warranty issues, filter issues, etc? Thanks

Only thing I can offer here is this:

Quote from the 2004 Duramax Diesel Supplemently Booklet:

Page 5-3:
".... It is acceptable to use diesel fuel containing up to 5% biodiesel (B5), but the final blended fuel must meet the sam specification, ASTM D975-02 (Grade Low Sulfur), as other fuels used in your vehicle, and the biodiesel used for making this fuel must meet the ASTM D5751-02 specification.

Biodiesel is produced from vegetable oils or animal fat that have been chemically modified to reduce the possiblilty of damage to you fuel system and engine. Higher concentration (i.e. greater than B5) biodiesel-containing fules or the use of unmodified bio-oils blended into diesel fuel at any concentration is not recommended and could damage your fuel system and engine. Such damage would not be covered by your warranty. If there are questions about the biodiesel-containing fuels you are using, contact your fuel supplier"

LATER!
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Booklet schmooklet.

Run the good fuel.

Black Max,

B20 (20% biodiesel) should be no problem at all. A lot of fleets are running B20. The New York State Thruway Authority ran B20 with no trouble at all in their southern region. They are not what I'd call big risk takers.

Higher concentrations of high quality biodiesel should be alright too, from what early adopters are reporting. In northern climates, gelling in winter is an issue. With pure biodiesel, arctic conditions occur in just below freezing. B20, with standard antigel additives, should be good down to around 0 F. Advantages include injection system lubrication, lower emissions, reduced diesel smell - and: more home grown fuel and less imported oil.

GM, like the other manufacturers is, very cautious about biodiesel from a warranty standpoint. It's still a relatively new thing, not in wide use. They don't want to pay out for bad fuel whether it be petro or bio. VW only recently went "official" accepting B5 in North America. - Excess caution when they've warrantied Euopean biodiesel for years, and hundreds of VW diesel owners in the US and Canada have been successfully burning B20 to B100 which is supposedly made to a lower standard.

Side effects? You might get some filter clogging at the beginning if you have a lot of miles on the truck and start running B50 or greater. Pure biodiesel is a great solvent and will flush out any sludge in the fuel system. The filter will do its job and you'll then have a very clean fuel system.

Keep us posted on what you find out in your travels!

Thanks for the replies. It sounds like running B5 would be OK with GM, and up to B20 shouldn't be a problem with filters on a truck with 50k miles. I wouldn't want to be changing filters on the road unless absolutley necessary. Thanks again.

So one could run B5 for a while to clean up the fuel system and then slowly start moving up with B20 to really clean things up? Does that sound feasable?