I have a Caterpillar 930H Loader with a C6.6 that will not start below 40 degrees. Starts and runs flawlessly above 40 degrees with no issues. If i plug block heater in for a few hours machine will fire.
Is your machine equipped with a intake air heater.? Does it work.? Post a Serial Number to help look up info.
Machine has glow plugs that are working. SN#DHC02654
Have you checked for any Active Diagnostic Codes reference the glow plugs.? According to the information I came across the engine should nmot require any type of starting aid assistance down to around 20 degrees. Is the engine cranking speed adequate.? What viscosity of engine/transmission/hydraulic oils are in it.?