Engine/Transmission (1994 - 1998) Temp guage

[TAllen]

My friend has a 97 CTD. His temperature guage goes from 140deg to 190deg in about 10 sec. then from 190 to 140 in aqbout 20sec. Could it be the sender or the Thermostat, or both? any ideas?



Tim

 

[az]

My 97 does the exact same thing, no clue hope someone does.