Was driving the car for a long period the night before without any issues what so ever. Parked it up that night (Saturday). Temperatures were recorded at -4 degrees that night as frost was setting in. And the next day(Sunday) was sapose to be -6 that night. But that day I went out to start the car after parking it up the night before she would not start at all. First thought heater plugs had given up, Tested them with multimetre and power is going to them. Tryed jump starting it as battery wasnt the best. Still no joy. Borrowed a computer and its not throwing up any error codes. Opened up pipe at injector to see if fuel was the problem. Turned the car over with the pipe loose and no diesel is spraying. Thinking the fule filter could be clogged. But previous owner bypassed fuel filter with a small inline one. Took that off and no diesel spilled out of pipe coming from tank and only a small bit going to engine. Looked closer to the diesel return pipes from injectors and plastic 3 piece hose connector was broke. Would that cause the car to be sucking in air and cause it not to start ? Anyone shine any light on this ? Will be getting all new hose piping and connectors and change all return pipes tomorrow.