I took this from this months copy of Equipment World... . Cummins has issued an alert to all it's dealers and customers regarding certain coolants. It says, in part, "Based upon available data, Texaco Extended Life Coolant and other similar formulations supplied by Equilon Enterprises should not be used in Cummins engines. " According to Cummins, these coolants attack some seals used in it's engines. This allows coolant to leak into the crankcase, where it reacts with the engine oil to form a thick sludge. Should that occur, says Fleetguard's Gary Spires, "The engine has to be totally disassembled and cleaned out; there is no shortcut. " Cummins is working with Equilon, Texaco and its supplier of seals to come up with a solution. For now, however, the company is telling customers to stick with traditional antifreeze, either ethylene glycol or propylene glycol.