the temp gauge on my 04 plate astra coupe fluctuates up & down but generally reads cold all the time , only when im sat in traffic does it get anywhere near the 90 deg mark , then goes down to cold again when the cars moving . car drives perfect & heater warms up as norm ! thanks in advance .

Glynn, January 2009

mine did the same thing until i got a leak in the water system. Nothing to worry about, Just keep an eye on coolantlevels and oil levels (same car y reg and they eat oil if your happy with the right foot!)
If you get steam go to a garage obviously usually a leak in the system.

Dave London, July 2012

replace thermostat

dave brom, February 2009