Im in the process of installing sensors for some monitoring gauges. Last one Im having just a bit of a brain fart with is my coolant temp gauge. Currently there is one sensor (for the ecu) located into a tapped hole in the waterpump housing. At first the obvious solution was to just use that hole and put in a T fitting and install another sensor. Which I have done, and attached a picture of. I have a couple concerns, the first of which is I was worried a small air pocked could possibly get trapped in the top of the T and give inaccurate readings. I suppose this could be fixed by putting a bleeder on top, but that seems like a band-aid to a poor setup. So another thought was to remove the waterpump and tap another hole for the second sensor in front of the first. Was just worried Im running out of room and was concerned about breaking the housing. So just wanted to ask what anyone thought or alternative ideas for sensor placement? Thanks

 

Can't tell exactly what's happening from the picture, but something like a coolant temperature sensor needs to be in the path of moving coolant; i.e., the sensor should not be located at a terminus.

 

+1
What he said

 

This is why I ask Thanks guys.

 

The other thing you've got to ask is, what is the purpose of this sensor? For overall engine temperature that an ECU can use, it should go in the main return flow after the coolant passes through most of the engine passages.
If it is to give you an early warning of overheating and imminent detonation due to combustion over temperature, it should go in the coolant passage that passes between the spark plugs (ie where the OEM gauge sensor is). Two different locations two different purposes.