Get a cheap infrared thermometer and take the temp of the radiator nipple where the upper hose attaches. Should be low until the thermostat opens, then go immediately to the thermostat temp.
Sounds like you are never getting up to temp. I need to put a cover over the grill in the winter to get up to temp so I have heat.
Here's what I mean for a temp meter:
http://www.harborfreight.com/catalog...er+thermometer