Was the thermostat in the end, which some reffer to as coolant actuator. Latter is probably more accurate since it's an electronic motor driven device which performs the same function as a thermostat.
It looks as though the thermostat housing had failed, and not at the classic location of where the unit attaches to the block either, but somewhere right in the middle. The garage has let me keep the defective part so i'll be ken to investigate the cause more closely. Not just ouf of curiosity but also to provide feedback to Audi themselves. A £300 pound part, in my view should not fail on a 6 year old car. Especially when any typical thermostat would cost less than £40 and probably be easily fitted by the owner and certainly not a multiple hour job for garage like this was.
I also believe that it's this leak which must have cause some kind of oxidation of the coolant which then also cause a secondary water pump motor to go - which shut off the stop/start function, and the level sensor in the coolant reservoir. All in all a very expensive, time consuming and frustrating few months.
I'll post some pictures up soon of the faulty part. Be interesting to see what anyone else thinks
Hello,
Did you change only the thermostat or the whole engine temperature control actuator n493
P2556 code, please help if you can
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Hello,
Did you change only the thermostat or the whole engine temperature control actuator n493