Only reaching 70 degrees after Coolant Sensor replacement

[ck_uk]

I while back I replaced the G2 Coolant Sensor in our A4 1.9TDI, as it was never getting above cold on the temp gauge. This seemed to solve the problem but it now only ever reaches 70 degrees, whereas the car originally used to sit dead centre at 90 degrees. The replacement is a green sensor opposed to the original black one. My only concern is that the MPG won't be as it should be now if the car is always running cooler than it should? Any suggestions?

[micheal balbrig]

Probably thermostat replacement next option.

[a4cvt]

I had the same thing happen. I replaced the sensor with a genuine replacement and the gauge still did not reach 90. I changed the thermostat and bingo,sits at 90 all day.

[kizzy666]

I had the same thing happen. I replaced the sensor with a genuine replacement and the gauge still did not reach 90. I changed the thermostat and bingo,sits at 90 all day.

same happened with me last year

[markoA4]

as said above go genuine all the time. plus probably time for a new thermostat. go genuine

[pauldazzle]

I while back I replaced the G2 Coolant Sensor in our A4 1.9TDI, as it was never getting above cold on the temp gauge. This seemed to solve the problem but it now only ever reaches 70 degrees, whereas the car originally used to sit dead centre at 90 degrees. The replacement is a green sensor opposed to the original black one. My only concern is that the MPG won't be as it should be now if the car is always running cooler than it should? Any suggestions?

Was the replacement sensor genuine VAG? If it was then you probably have a stuck open stat or an air lock.