Lamonte, the temperature sensor should be located up around the temperature regulator housing.
Another thought I had happen with 3126 B, the pac-brake located on the exhaust side of engine,
sticking and not opening all the way and increasing exhaust back pressure on engine above 40psi,
and woud cause engine to heat. Found air cylinder was stuck and movement of gate valve about
5/8 open ( after tear down had to replace the air cyylinder.) If you have a hydraulic fan it is possible
hydraulic motor on fan is not producing enough rpm"s. and needs rebuild or replacement. One
thing in the thermostat replacement, the jiggle pin is not installed in correct location on the
smaller thermostat housing. Going back to the above temperature coolant sensor, you have a very
high temperature reading and light and buzzer going off. when this is happening there should
be fluid or steam coming out from the little hose just under raadiator cap. there should be coolant
loss in top tank. If there is no coolant loss will again point to temperature coolant sensor. One
more thing did mechanic bleed the aiir from engine head after thermostats were installed.
Dave Atherton Retired Cat Mechanic