Originally Posted by Junkman

I've never had much luck turning with the PS nut when glow plugs are in. I usually use a remote starter switch connected to the box on the passenger fender OR remove the fan and reinstall the bolts that hold the pulley on. Then it is easy to use a 27mm socket.

The decision depends on what level of precision is needed and whether you'd prefer to remove the glow plugs, fan or try the switch multiple times to get is close enough.