Best place for aftermarket water temp sensor
 

I'm sure this has been covered before; however, I could not seem to find an answer. I know of three main places to mount an aftermarket sensor, drill through the waterpump, on the upper hose, and on the radiator. Any thoughts on the best place? It just doesn't really make sense to me why you would mount a sensor after the thermostat, let alone the radiator...

In water pump under the thermostat is best. That's where the ECU thermosensor is.

dont we have a drain plug in the front rotor housing that most sending units thread right up to ?? thats where i was gonna put mine

I chose the filler neck.

https://www.rx7club.com/showthread.php?t=137825

Scroll down 3/4 for pics and comments. :)

The best place is always just prior to the thermostat, in any system. That will generally be the hottest point in the system, short of localized hotspots. For this reason, most of us put them in the waterpump housing...right beside the stock one.

Here's a cheater tip. For those of us with removed air pumps, who never intend to reinstall them, you can actually use the right-most airpump bracket hole on the WPH to mount your sensor. Just drill right down into that hole all teh way through. THis is nice because it's already perfectly straight for you. IT is not obstructed by anything inside. Retap the threads to match your sensor and you're good to go. Just tie the wire back out of the way of the belts on the waterpump/alternator. This could probably work okay for someone who wanted to cut their stock airpump bracket but keep teh air pump...you could structurally do without that one bolt/hole, the other 2 would hold it on just fine.

What about this idea? 3rd post down

https://www.rx7club.com/showthread.p...d+valve+switch

So if I drilled and tapped through this sensor would my AC be useless? Am I confusing the water thermosensor and water thermoswitch?

That's the thermofan's temp switch. The switch itself has nothing to do with the A/C, it just switches the fan on if coolant temp gets to ~205degF. However that's on the wrong side of the thermostat. If you have a thermostat stick closed, the gauge will read below normal temps while the engine cooks itself...

Brilliant! :bigthumb:

Yes, the hex key plug. That's where mine is, good location and reads temps from the block so I like it. When it reads ~180º the stock temp gauge shows just under 1/4 and when it shows ~185-190º it shows 1/4 or a little above on the stock gauge. Works nicely.

dDub- Do you happen to know the thread/pitch for that hex plug? I see you have an autometer water temp gauge, what size thread is the sensor? Did you have to get an adaptor for the senser to fit?

When I got the autometer gauge it came with the sensor and a larger adapter with threading in the middle for the sensor. That adapter threaded right in place of the hex key bolt, don't know the size of it, though, sorry.

As a general rule of thumb, you want the sensor to be at the hottest part of the cooling system.
As mentioned before, this is where the thermostat is.
Now, there is debate whether you want it before or after the thermostat...
I prefer after the thermostat, as you can easily see when the thermostat opens.


-Ted