Hello guys can c anyone shed any light in this for me please I have a 150 bhp 1.9tdi that over heats when driving if I coast temp drops down again I replaced water pump and did a ahead gasket sniff test and it came back clear. I have blow into the big pipe below and water came out straight way I blew into the smaller hose and covered the plastic nipplease and air just blew back at me when I removed my mouth. Is that normal? Also return flow to resivour is a trickle at best on tick over hot or cold ill attach image now