2003 Suzuki LT-Z400 Factory Service Manual, Page 128Get this manual
COOLING AND LUBRICATION
Check the closing or opening temperatures by testing it at the bench as shown in the figureConnect the thermo-switch to circuit tester and place it in the oil contained in pan, which is on stove'" Heat the oil to raise its temperature slowly and read the column thermorneter when the switch closes or opens
Multi circuit tester set Tester knob indication: Continuity test