low temp on gauge below 45
 

Hi all. I have a persistent problem with my beloved vw polo. The temp guage doesnt seem to go above 45 when driving. I left it started in the drive and it reached the 90mark but has failed today whilst doing a 30mile stretch on the motorway. This has been going on for around a couple of weeks now, didnt think it was a problem at first but now a little suspicious, would love some clarification or advice.