changed the stat. sounds so simple doesnt it. ffs.. 
Yep, sounds so casual don't it, like it takes about five minutes. It took me about three hours to do mine. I was in the 'V' in under thirty minutes, wiggled and waggled the thermostat, snapped the transfer pipe bracket off by accident (which didn't bother me as i had bought all the new bits anyway) and then the real fight begins. Pipe grips one end and mole grips the other, the bloody thing put up hell of a fight. If I had to do it again, I'd saw through the stat housing outlet pipe, hoover up the swarf and then unbolt the stat.
As a side note, do you think that Vauxhall measured the longest length of transfer pipe that would fit through the 'V' side of the engine, and then added 5mm so that it wouldn't.

With the exception of the transfer pipe it is a nice little job.

The jobs I hate are suspension related, where everything is so damn tight because of thread dryness and the dirt.
