Audi A3 52reg 1.6 8v new water pump head gaskit thermostat and still over heats the cooling fans dont kick in BUT if i take the stat out it dont overheat and the fans come on dont make sence do you think the rad is blocked cheers

take the top off the filler cap run engine to boil. keep it full off water to the top. you will see air bubbles coming out as the engine gets hotter. squeeze the pipes on the rads to help the air come out. when fan kicks in turn engine off and leave to cool down.while you are doing this make sure the fan for heater is off but is on full heat. can have fan on number one on speed that is fine.

if you have replaced the radiator hoses.t-stat,water pump and no water in oil then you could have a cooling fan not operating(assuming it has an electric fan),or a bad head gasket or plugged radiator that is not allowing enough coolant flow.you need to check and make sure the cooling fan is operating if not then it will have to be fixed.pressure test the cooling system and check for leaks(external) and have the system checked for gases in the coolant with a head gasket test chemical.as far as the rad being plugged it will have to be removed and flow tested.

CLUTCH ON COOLING FAN FREEWHEELING. COOLING FAN SHOULD HAVE RESISTANCE WHEN TURN WITH HAND WHEN ENGINE HOT.IF NOT FAN FREE WHEEL FAN CLUTCH NEEDS TO BE REPLACED.IF COOLING FAN OKAY.YOU COULD HAVE BLOWN HEAD GASKET.YOUR RADIATOR AND ENGINE BLOCK NEED FLUSHING OUT.CHECK WATER PUMP FOR LEAKING WEEP HOLE IF LEAKING REPLACE WATER PUMP.

have your cooling system thermostat check....

Turn your A/C fan to the highest setting and verify if your cooling fans are coming on and staying on. If not then there is a problem with the cooling fan circuit.

sounds like a head gasket leak, you can buy a kit at your local auto parts store , that you can stick on your radiator and will change color if exhaust gasses are present in the cooling system. alumiseal does a great job of sealing leaks on the straight 6 motors on these models

The main reason for the over heating of the audi tt is to do with the water pump. The propeller within the first type of water pumps is made of plastic. This was to prevent corrosion, however was never designed to last longer than 5 years. What you need to do is purchase the new style water pump. These new style water pumps have been designed with a metallic propellor which should resolve the overheating. Let us know how you get on.

is the oil/water a milky colour? if so, then yes, your head gasket has blown

Did you replace the THERMOSTAT?? also make sure you get all the air out of system

You actually need the thermostat in to pressurize your cooling system or the coolant won't cyle through the radiator, it'll just cycle around the engine. Most people think without the thermostat in the coolant will just pump freely through the engine and radiator, but it doesn't.

Chuck in a new thermostat, purge the air out of the system and see if it overheats then. I gaurentee it won't, if it does then you've got head problems (but they should already be obvious by now).