S type overheating

[Tony777]

I've got a Jaguar S type 3.0 V6. Had a problem with the plastic T pieces  cracking up so replaced them with brass connectors, then I saw the plastic part on the top hose had a crack so replaced the top hose and at the same time, replaced the thermostat at the same time. 
Started her up, thought I got all the air out but she overheated again, so I thought the new thermostat was faulty. Took the thermostat out and it was fine, but never warmed up. Bought another new thermostat, fitted it, bled the system, took her for a run, no problems except when I let it tick over for about 5-10 mins and the temperature went up again. Drained the system, more new antifreeze, started her up, still overheating. The pipe to the top of the thermostat housing, nice and hot, the pipe to the left of the housing was nice and hot as well, but the pipe underneath the housing was cold. Any ideas what to try next? 
By the way, I done the "sniff" test and that was fine so no worries with the head gasket.
I also changed the plugs and a coil at the same time plus done an Oil change as well, but that shouldn't have anything to do with it

[Russ68]

Hmmmm, bad luck Tony, this one has been fighting you! I'd have said headgasket, but you've checked this, no emulsion under the valve covers and Oil filler etc? Otherwise, how's your radiator and water pump? Plus the drive belt?

I also have a 2001 3.0, my only overheating was caused by a leaky expansion tank. But I'm can see I'll need a new radiator at some point. Good luck!