· Retired Moderator
If the radiator is cracked, the cap wont releave anything because of the crack already releasing the pressure. The normal temp for a 4.0 is 210... and the temp is picked up buy a sensor near the thermostat housing. Its a 2-wire plug in I believe. I don't know of a way to test it, but it sounds to be working fine. The steam was prolly from the crack in the rad splashing a little coolant out. Replace the rad and you should be good.