Will not start when it is cold?

This can be caused by two things either the fuel filter needs to be replaced or the glow plug starter has gone bad. If you have not done the fuel filter it would be a good idea anyway because it can rid the system of water contaminants as well. If that doesn't help, I would do the glow plug igniter. Please let me know what happens.

Hello,

It sounds like you might have an air leak in your fuel system. This is very common on your car. The usual sources are the leak off pipes between the injectors (see image below) or the fuel filter seal, or the hand primer bulb. A simple test is before you first start the car pump the hand primer under the bonnet until it is hard, and it should start pretty much first time. A good test is to see if the hand primer bulb is soft when not starting, this will indicate a fuel leak (see image 2). This problem can be hard to trace as leaks in the pipes suck fuel in as opposed to leaking diesel out so there are no visible signs.

A blocked fuel filter can also cause a hard starting issue.

Have you checked the glow plugs?

Cheers, Boris