Wizzard...Your Cat man said BD ran too hot?? Could that be possible?? I don't think you had a hot batch of BD...you had a bad Cat mechanic that didn't know what caused the problem so blamed the BD. Besides, if it caused the problem in that one engine, why not the other??

BD has a lower BTU content rating that dino D...it can't burn hotter. Here's a blurb I found online talking about BD vs. #2D combustion properties.

http://www.cytoculture.com/Biodiesel...n%20Properties
Heat of Combustion Properties

Relative to petroleum diesel no. 2, Biodiesel has a slightly lower heat of combustion on account of its oxygen content (petroleum diesel hydrocarbons are not oxygenated). The heat of combustion for soy methyl esters is 128,000 BTU (British Thermal Units) per gallon vs. 130,500 BTU/gal. for petrodiesel. In the Southwest Research Institute study (1996), the heat of combustion for rapeseed biodiesel in blends were compared with petrodiesel. Petrodiesel had 18,400 BTU/lb., neat biodiesel had 16,200 BTU/lb. (88%) and a 20% blend of rapeseed methyl ester biodiesel had 17,900 BTU/lb. (97%). However, with the added oxygen, the net combustion efficiency for the blended fuel is increased, which should compensate for the slight drop in BTU content. The differences would be most noticed at low rpm and high engine load when the engine would most benefit from more oxygen.