Help!! Work at a garage and had an Audi A3 in today. Water circulation problems. Engine runs at a steady halfway temp. Runs and ticks over fine. Heat through the heaters. Radiator stone cold and pipe from thermostat housing to bottom of radiator stone cold. Fitted new water pump, new thermostat housing plus switches and new radiator but still the same problem. Got to go back to it tomorrow morning and wondering if anyones got ideas??? Cheers