300 tdi cooling system

disco 300 tdi the small pipe from the expansion tank goes through a union one to the thermostat and one to the radiator should water be restricted through the union help please

IMHO all these 4x4s that have engines north-south need redesigning so work out the plumbing yourself. (the problem is that the water pump gets to be the highest thing on steep hills) Also IMHO any car that has bleed screws in its cooling system is extremely suspect as a proper cooling system should vent air automatically. (see "Steam Trapping and Air Venting" which whilst it is not an automotive book is nevertheless highly relevant but evidently not read by naive engine designers)

Saab cured the Dolomite engine that they bought the manufacturing rights for by fitting a low-down water pump outboard of the block. Problem solved.

The threeway joiner can have a tendency to leak, afaik can be replaced with an ordinary T piece.