Coolant Temp Sensors calibrated to location on engine?

[93turqxj]

After i put my stroker in the jeep i realized that the boss at the right rear of my engine wasnt tapped for my temp guage sensor.

So being the lazy ass i am i drilled and tapped into the tstat housing next to pcm temp sensor and its reading 260* wtf???

i know its not running hot because the fans stay off then come on after ~30 min of idle and/or when i turn a/c or defrost on... so they working as should

so my question... are the temp sensors calibrated to their spots on the block? because when you think about it at the rear of the engine cold coolant is coming in and when it gets to the tstat housing it has absorbed the heat of 6 cylinders thus getting hotter, and the pcm has adjusted for it at its sensor on the tstat housing to cause the fans to turn on at the "210" degrees

if that makes any sense at all

[92tank]

do you have the right sensor? iirc there are three diferent ones. the resistance is different. i had the same issue once and it was just the wrong sensor.

[93turqxj]

Three sensors are cts for pcm. Gauge, dummy light

The 93 Cherokee has two of the 3, either a pcm and a gauge or a pcm and a dummy

My problem is that I relocated the gauge sensor from the rear of the engine to the front and in theory the coolant at the housing is going to be significantly warmer than at the rear where the coolant has been cooled by th radiator...... That's IF my theory is correct

[92tank]

once warmed up the coolant should be the same temp or close to it. cause the coolant runs though the block first than to the back of the head.

[93turqxj]

No it runs the opposite way, through the lower into block back through the tstat housing back to radiator

[gonridnu]

Did you use the exact same sensor that was in the rear position, as in the one that was on the Jeep before? I purchased the "correct" sensor from the aftermarket (Napa) as a matter of habit for my rebuild. It read way high, like 50 degrees high. I put the stock one back on and it matches the measured temp. I've had this issue in the past too. I chased it on a customer's corvette once and got 2 sending units from the aftermarket before going to the dealer and getting one that gave a correct reading at the gauge.