Zr 105

[Chucky1012]

Hi all ive recently changed my engine in my zr as old engine went bang unfortunately ive got a problem with the cooling system sometimes it pressuring and it chucks out white smoke. been told it could be a couple of things- major airlock or blocked radiator or dodgy thermostat but whats making me wonder is the heating works fine. I know its not a Head gasket failure as its got no signs of hgf also its not long had the hg done etc... the top rad pipe gets hot but the bottom pipe by gearbox is cold is that normal? Im not a mechanic so dont know if its okah or not....... any ideas people?

[JOHNDQ]

No check the rad and Thermostat