A3 Temperature Gauge Eratic?

[-JC-]

Hi guys, bit of a n00bie here!
I have a 2002 1.9tdi A3
Since I bought her last week, the temperature guage is always wondering between 90 - 110 Degress?
Never seems to overheat and never causes problems, is this a temperature sensor replacement needed?

 

[-JC-]

ps the heaters blow HOT air and cold when cold!

 

[s3dave]

Sounds like the switch/sender could be faulty

 

[coyle]

coolant temp sensor?

 

[Imteyaz]

+1 for Coolant Temp Sensor.

If that doesn't sort it, then the thermostat is your next suspect.

 

[CHRIS555]

+2 Coolant temp sensor - extremely common fault - i'm changing mine today funnily enough!

 

[kite]

change the CTS first.
I suspect the water pump impellor has come off the shaft....