[Solved] Engine Coolant Temperature Sensor location?

You want to have the engine running so that it can get to temp and have the thermostat open so that the coolant can eventually push the air out until the coolant comes out the top.

Having the heater on makes the whole system full of coolant.

 

As i recall now, if i do it like this, coolant starts coming out of the ECT socket

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Do you know if the ECT sensor provide both temp and high temp light in the dash as I disconnected it and both the light comes on in the dash and the temp stops displaying in the ODB II phone app. the lower temp sensor with pink and black wire bellow the EGR what is it purpose? OBvious provides temp but since I disconnected the top sensor I dont get any reading, any thoughts
?

 

Thanks for providing the full background information in this one. The thread where the most progress toward an answer might happen seems maybe to be this one over here.

 

Found the issue nothing was ever wrong my app simply only showed one sensor. added the second.thanks for the help Chapmanf!

 

Cool, I thought it might be something like that.

Now ... did you happen to figure out which one is 7C0 and which one is 7C4 ?

 

Yes the but I need to confirm 7c4 has a higher temp so it is closer to the engine block.might be for my car or all gen 3 2010 are numbered this way making it the sensor with the pink and brown wire.

 

Hello quick question when I bleed air do I take sensor off and turn car on then put sensor back on or just take off for a moment and then put it back then turn on car ?

 

With 2011 model year you have the bleed valve integrated into the sensor. Before pouring coolant back into the reservoir (if for example you’d drained 2 qts previous, in the course of EGR cleaning, more info on my signature), unscrew the white cap a few turns.

If you want to avoid spilling, and be able to see clearly when coolant starts coming out, push a short length of clear tubing onto the bleed valve’s spigot, and direct the tube upwards.

Then start pouring the coolant in. Hold your hand at the bleed valve (or attached tubing: you should feel a gust of air venting, as you pour. If you don’t, you need to open the valve a bit more.

You’re basically providing an exact route for air in the system, that will flow out as the coolant flows in.

Eventually the coolant level will reach the bleed valve, and you should close the bleed valve before pouring more.

* More info on why

 

For the most part, as you are pouring coolant into the plastic bottle and it is flowing from the bottom of the bottle, in the hose I colored red here, into the top of the radiator at the near side, the air from high points in the system (the top of the radiator at the far side, and the nipple on the top of the outlet pipe from the cylinder head) simply flows through the hoses I colored blue here, right back into the plastic bottle through the connection at the top, which is above the coolant level, and out through its filler mouth around your funnel.



Those blue hoses are the same route the remaining air follows to end up in the degas bottle while you are running the engine up to temperature the first time.

The bleed valve in the tee in that exhaust heat recovery hose (only present for 2010-11) seems really kind of superfluous except for a little bit of air that would get trapped in that inverted U of hose there. They might have figured out by 2012 that they could let that small amount of air just get pumped through and find its way into the blue hoses and back to the degas bottle anyway.

 

Have to confess: I can’t recall if I’ve done the feel for escaping air thing on the Prius. Now I will for sure, next time, lol.

 

Still, when refilling the reservoir (with the coolant air bleed valve open), I had a clear tube pushed onto the spigot, and at some point it DID start showing coolant. Not sure what that amounts to, if it indicates there was air exiting and finally just coolant. Would seem to be?

 

Sure, if you have the 2010 or 2011 and the valve is there and you open it, stuff'll come out.

They seem to have decided by 2012 the system clears itself of that last bit of air effectively anyway (unless they put some new instruction to the contrary in the 2012 repair manual, which I haven't checked).