Owned 19yrs, now for 20
Join Date: Jun 2003
Location: where havn't I lived? Now in Erie, CO
Bronco Info: 95XLT351 E4OD SAS 44/ARB/Alloy shafts-joints. D60 rear/Detroit. 4wheel disc,37" MTR Kevlar, 4.56etc.
yea, maybe thermostat, but why is everyone telling him to go buy and replace it? If the radiator has a motor input and return hose, then....just like our bronco or really any motor, once it starts warming up, the Tstat will eventually open. What happens? the intake hose to the motor (from the radiator) will stay fairly cool to the touch, and once that Tstat opens, the return hose (to the radiator) will be warm in winter, hot in summer. If you can't feel any warmth in the radiator return hose, then sure enough the Tstat is not opening and needs replacing. If that does happen, that's likely not the issue.
Other things you never really mentioned that help in diagnosing problems:
how many miles on the vehicle, and how long since the coolant has been flushed/replaced? How old are the hoses? no leaks I assume? is the radiator original, as well as Tstat? fans working properly, original fan shroud in place around the fan?