The heater is hooked up on this truck, and it climbs in temp slowly, so I don't think that's it. Didn't do it with the old t-stat, either.
Some of my crap:
1963 C-30 flatbed dually 292/SM420
1965 C-10 LWB fleet 250/column shift 3 speed
1965 C-30 9' stepside 250/SM420/4.10 gears (my DD)
Website I made for my crap:
http://www.66submarine.com 
