Astra Coupe engine temp probs

Hello,

I have recently bought a "51" 2.0l Turbo astra coupe with 55k on the clock
and a FSH.

I have just taken it for a spin in the hills, first dry day since I bought
it, and I have noticed a problem with the

engine temperature.

My old 1.8 Astra's temp was always bang in the middle of the gauge.

I have noticed with this one the temp is all over the show, anywhere form
cold to midway.

I especially noticed it when I had the heaters on full, with the windows
open feeling the wind in what is left of my hair.

The temp was reading "0". I thought the sender had come off, until I turned
the heaters off, everything seemd back to normal after

10 minutes.

I tried it agin a while later and it happened again.

Any help would be gladly appreciated.

 

Sounds like thermostat is stuck open.
Start the car up from cold and feel the radiator pipes. They shouldn't get
warm till guage is showing about 95 degrees and stat opens then you should
feel warm water flowing through them and rad getting warm.
If pipes warm up straight away as engine temp increases, stat is stuck open