When there is adequate air flow through the grill due to forward movement, the water temp will hover around the thermostat rating, be it 180°F or 195°F.
With less than adequate air flow through the grill, as in traffic, and off road, the water temp will be between 195°F and 215°F, as that is what the ECU is programmed to maintain through electric fan cycling.
If you are trying to lower the engine temp off road, a lower temp thermostat won't be what you want.
On my 2008 JK, I removed the electric fan, and installed a mechanical fan and shroud.
The engine hovers around thermostat temp, (195°F), on and off road.
The auto transmission's temp is lower on and off road.
Under-hood temps are lower off road, which lowers the intake air temp.
2008 Unlimited Rubicon Automatic
Last edited by ronjenx; 09-14-2012 at 07:03 PM.