Bust the Myth
Pump Seizures & Filter Concerns: Biodiesel will cause filters in oil burner systems to "freeze" up or "seize."
"Biodiesel [100% biodiesel, or B100] is a good solvent. It may loosen or dissolve varnish and sediments in fuel tanks and fueling systems left by conventional diesel over time. If a system contains sediments, the tanks and fuel system should be cleaned before B100 [biodiesel] is handled or used. A good indication that [a] B100 is cleaning the tank is an initial increase in filter plugging. Over time, filter change intervals should return to normal. This should not be an issue for B20 [a 20% blend of biodiesel in heating oil] or lower blends."
Biodiesel is incompatible with rubber seals and pumps utilized in oil burner systems, thereby causing this equipment to fail.
"B100 [100% biodiesel] is not compatible with some hoses and gaskets. B100 [100% biodiesel] may soften and degrade certain types of rubber compounds used for hoses and gaskets (buna-N, nitrile, natural rubber) and may cause them to leak and degrade to the point where they crumble and become useless. There have not been significant material compatibility issues with B20 [20% biodiesel blended with heating oil] unless the B20 has been oxidized."
Biodiesel will cause heating oil tanks to corrode.
"There have been reports of accelerated corrosion in ultra low sulfur diesel tanks across the country. The definitive cause of the microbial contamination is not yet known; however, the EPA and industry are [investigating] the cause and are working towards a solution. Following best practices on maintaining tanks, cleaning them, and removing water bottoms reduce the risk of corrosion."
Biodiesel is negatively affected by yellow metals, such as copper, that are present in many oil burner systems.
"Copper strip corrosion. [The copper strip corrosion] test is used to indicate potential difficulties with copper and bronze fuel system components. The requirements for B100 [100% biodiesel] and conventional diesel are identical, and biodiesel meeting other D6751 specifications always passes this test."