mystery overheating, please help????

[alistair666]

hi guys

having a prob with my 2000 a3 1.8t sport

noticed my dash temp gauge wasnt reading so changed the sensor
and thermostat. Changing the thermostat i jost nearly all of the coolant, i filled it back up but now im having overheating problems

car rises to temp as normal but gauge sticks at 90oc as if showing a false reading, fans dont come on and if left will boil. Have done the aircon code 51 check and that sticks at 90 as well. noticed the bottom hose comeing from the thermostat going to the rad stays cool all the others are hot

had the water pump changed with the cam belt a few months ago

thinking probably an airlock but not sure why gauge or fans wont work

any help greatfully recieved

 

[golf]

Could be an airlock or the thermostat is not working as it should, assuming the water pump is still OK.

 

[Clach]

try the heaters, if thet get colder instead of hotter..it's the water pump

 

[Broken Byzan]

Either stat not opening cos its faulty or because is airlocked and not getting heated by water to operate correctly.She needs bleeding, i am not 100% where to bleed an A3 without checking, but i bet it via a heater hose the same as an A4

 

[alistair666]

cheers guys

im am getting hot air out the heater vents gonna take out the stat and check it in hot water

could still do with some help with bleeding air out the coolant

still a bit confused as to why the temp gauge just goes up to 90oc

 

[abdus]

just try removing any air locks before anything else. while still cold, remove coolant expansion bottle cap, start engine, put blowers on full blast and leave it for some time.

you should be able to see some bubbles coming out if there is any air lock.