The WK2 Jeep Grand Cherokee with a VM 3.0 diesel engine fitted does not have a coolant drain plug in the block.
This makes doing a complete cooling system flush on the vehicle challenging at best.
The most effiecent way to do this flush is using a coolant flush machine but not all workshops have these and almost and DIY repairers will not.
If you cant get a coolant flush machine the best way to do the flush is to remove the thermostat housing on the front of the engine and remove the bottom radiator hose at the engine. using the garden hose you can flush the radiator and then flush the block. Be sure to have the heater for the climate control set to high temperatures before you do this.