I just got an after market water temperature gauge and would like to "T" into the stock temperature sending unit. Does anyone know where the stock sending unit is, and what size the fitting would need to be? Thanks.

 

you're looking for the coolant temp sensor? it's screwed into the block. doesn't the temp gauge come with a sensor you put inline with a coolant hose?

 

It does, but I thought it would be a good idea to just tee off of the stock sensor. I was thinking the heater core lines, but do you have any other suggestions?

 

well it would depend on the size sensor it came with. heater core lines and radiator input/output hoses are different sizes. water temp gauge sensors i've seen(not many) were sensors built into a piece of pipe the size of the radiator hose and you just cut the radiator hose and put the sensor in-between where you just cut and clamp it down.

i don't think tee'ing into temp sensors would be universal. there's some sensors that have linear voltage increase, and then there's some that have a switch and resistor in them. the latter works that say a sensor is rated for 300 degrees, from 0-150 would be 0-5v, then a switch inside would turn on a resistor and the voltage would drop to maybe 1v, and then from 150-300 would be from 1-5v again. it's like using 0-5v twice for the full 300 degrees. for reference, ours is linear and i don't know if aftermarket temp sensor would have the same calibration.

 

This sensor is just a 1/8 NPT probe (Autometer). I figure T into the water line, put the appropriate barbs at the two ends, then the correct reducer on the other and put the sensor in the reducer. What size is the heater core line? Should I splice somewhere else, because I think the heater core would be best?