General Temp guage question

[Rickbarr]

Hi all and a happy weekend.. I have a 1986 T3 Westfalia with a 1.9 non turbo Diesal Aspirated conversion. Recently after a bad overheat: had the head gasket replaced, new rad and water pump , re-did air ducting, cleaned water pipes also updated exhaust system. Engine is running happier then it ever did but my temp guage used to allways sit around 12 o-clock until I did all the repairs. After I updated the exhaust (last project) The temp gauge barely get s past cold even when climbing hills. The low speed cooling fan still comes on like it s supposed to, usually if I m sitting at idle or when driving slowly on a sleep decent. I m in Portugal and outside temp at the moment usually 20C durring day 10C at night. I' m happy my Engine is running nice and cool but I dont want to run it cold. I was thinking my thermostat was stuck open but why would the cooling fan come on if that s the case ? Is my sensor bad ? Or in some circumstances is it normal that this engine just runs a lot cooler when the exhaust, air , and waterflow are all nominal ? Cheers..