Here's a response I received on 7/7/2003 from New Holland.
Thank you for contacting New Holland North America. Please accept our apologies for the delay in responding to your email. Normally, we are able to respond to inquiries within a few business days and we hope to be able to serve you better in future.
The use of biodiesel blends meeting ASTM 6751 (see attached Appendix for more information on ASTM 6751) is approved for New Holland engines up to a B5 (5% blend ratio). Biodiesel fuel blends can be used in all CNH produced engines. Some problems with elastomers o'rings, seals, etc.) may be experienced with older equipment though replacement service parts should remedy this situation.
However, please note that since biodiesel does not have long-term stability, it should not be left in engines that are stored for more than four months. Also, prior to storage, engines should be flushed by running for a minimum of 30 minutes with regular diesel fuel.
Since biodiesel fuel has a higher cloud point than conventional diesel fuels, its use during the winter months should be discouraged in favor of a blend of #1 and #2 conventional diesel fuels. Biodiesel fuels attract moisture and may contain higher content of water than conventional diesel fuels. It may be necessary to drain the fuel filter water trap more frequently when using biodiesel fuel.
Additionally, depending on fuel quality, it may be necessary to change the engine fuel filters more often when using biodiesel fuel. If biodiesel blends are spilled onto painted surfaces, they should be wiped up immediately or they can damage the painted surface.
On the plus side, biodiesel contains no sulfur or aromatics, and is an excellent lubricant. It has a higher cetane number and burns cleaner than diesel fuels and produces less particulate and smoke emissions. It mixes easily with conventional diesel fuels and does not separate once it is mixed. It is considered an environmentally friendly fuel because it is a renewable source of energy. Pure biodiesel fuel is biodegradable and non-toxic to animals and plant life.
New Holland is presently evaluating blends greater than B5 and will issue the results to certified New Holland Dealers via Service Bulletin once the results are available.