X30 water sensor location

I’ve purchased a used IAME X30 Senior and I’ll install a Mychron with water sensor.

I’ve seen that X30 has two fittings: one on the cylinder head, behind the spark plug and another on the thermostat on the water pipe. Where should be the water sensor placed?
I’d say that on the cylinder would be better because it’s closer to the engine and it may alert earlier in case of overheating cause by water leakege, but I’ve seen X30 with the sensor in the thermostat so ot sure about the difference.



correct me if I’m wrong but I believe that the bung fitting on the cylinder head is used only for bleeding the cooling system. I have always run the sensor on the thermostat in between the hose, I’ve never seen anyone use that fitting to place the water sensor. Running it by the thermostat seems to make more sense anyway, there is a ton of heat generated by the cylinder head which will throw off your reading. I’ve never seen anyone have a failure that was related to inaccurate temperature by putting the sensor on the thermostat, in fact every article I’ve seen states the optimal temperature (around 125-130f or 51-54c) which is taken from the thermostat itself.

1 Like

Thank you for the feedback.

If you look at that image from a Power Republic video, you can see the sensor in the head fitting:

I believe that’s the Super x30 175cc engine in the picture. You have the 125cc engine correct?

Yes, I have the 125cc. Noticed it was a little different but was thinking that behavior was the same. Anyway, if the “standard” is thermostat, let’s go for the thermostat. Thank you!

Use the fitting in the head. If you lose your coolant, the sensor will show you a constant rise in temperature as the coolant leaks out.
A sensor in the thermostat will show you a brief spike in temperature when no longer immersed in coolant then return to a some what normal reading all the way until your engine seizes.

If you think of it as a water sensor, you don’t want the head temperature to be throwing that temperature to the extremes, for everyone I have seen who races x30 (including myself), we all run it in the hose which will take the water temperature, compared to in the head, which will take the water temperature but it will be much hotter and inconsistent compared to a stable increase. and as long as its under 60 degrees you’re good.


I’m with Declan. Bear in mind also your MINIMUM temperature is 45 (maximum 65, optimum 60) and you can damage the engine pushing it cold. Having your only temp sensor in the head gives you a falsely high indication. You can measure the head temp also for accurate tuning but use a mychron 2T. I’ve never been that way inclined, in the hose thermostat is perfectly adequate.