Xud9 coolant pipes at rear of engine

[Donny165]

On the back of the xud9 engine behind the water pump there is the alloy casting housing for 3 pipes the main one for the radiator the one for heater matrix and what's the other one for and which of the 2 small pipes is the correct one for heater matrix
 Thanks in advance

[Mighty306]

Hopefully these will answer your question. The outlet tank from the block is also shown on the diagram with the hoses, but not numbered.