t reg 2,.5 v6 auto tem runs fine then all of a sudden it will go up to 100 put air con on temp comes back down if you switch car off leave it a min put ignition back on tem gauge above 100 start the car after a few seconds it drops down to above the 90 any ideas thanks

paul, May 2008

Suspect a dodgy coolant temp sensor on your Omega as its a common fault on all the vauxhalls. Mine was the same on a Astra TD

BMS2007, August 2008