Re: 1994 150 Econoline Conversion van
Highly probable that your t-stat is shot, especially if it's stock. Easy and cheap fix ($8 or so). Had the same problem with my old Spirit, you could hear the water boiling in the rad, it was neat watching all the folks sitting on the patio at the local coffee shop stare at my car.
Edit - I forgot to mention that the car also required a new head gasket since it warped from the high heat....good luck
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!