Overheated Prius Motor, Have some questions.

I used a scangauge II, it's one of the basic built-in gauges (you can also program in more esoteric ones). It was great for filling the info gaps, but after about 3~4 years constantly connected to the OBD port, I started getting Check Hybrid System warnings and return-to-basics brakes. Dealership ultimately suspected the Sangauge, and I think they're right: when I disconnected issues went away.

 

Started it up in the morning

The engine first shut off at 103



Then when I got to work, I parked and it showed 159 right before I pressed the power off



Sweet, the scangauge II is great.

 

I think maybe I will only use it on long trips

 

159F. How far is work drive? Catch can is a must if that was your peak temp.

 

3 miles
Installing the OCC today or tomorrow after work

What should the Peak temp get to?

 

Thermostat in the Gen 3 is 195F. Car will eventually run at that doing highway speeds and will hit 200 climbing grades then come right back down.

 

Great,
This will be fun to monitor on the ScanGaugeII, while I drive around

Thanks

 

"This will be fun to monitor on the ScanGaugeII, while I drive around"

Among many other parameters, you can also monitor the coolant temp of the inverter/converter.

 

I've had mine continuously connected from 32 miles--when I bought the car new--to 82,000 miles six years later.

 

That is good to know,

Thanks

 

I first had the chips in our old Scangauge II updated, then programmed in some Prius-specific codes and have been using it continuously since 2013 and currently have 95,000 miles on it. Personally, I would avoid repeatedly plugging and unplugging the Scangauge into the OBDII connector socket, as that repeated action may damage the connecting socket.
I routinely monitor coolant temp and can confirm the 103-degree F engine cutoff and the stabilizing at 195-200 degrees. I have a lower inlet airblock with movable doors, and with those doors closed and climbing mountains in warm weather, I briefly got over 200 degrees and thereupon pulled over to open the doors, which solved the overheating problem.
But be advised that if you have a really old Scangauge you may have to get updated processing chips installed inside so that the Scangauge can be successfully programmed with the full set of Prius-specific codes.

 

This is another good reminder that most humans are generally not as good at multitasking and interrupt handling as they think they are.

I have an advantage here in knowing that my such skills are below average. So I can get feisty in pushing back when others insist that I perform at the level they believe (often wrongly) that they can do themselves. This pushback has significantly reduced my rate of errors and eff-ups.

 

I wouldn't consider 200 overheating at all. A 5 degree temp swing is a pittance and most cars run well above their thermostat setting, especially in summer. My truck will run in the 220 range hauling up a hill and a Camry I had floated between 190 and 205.

212 is boiling for water but the engine coolant loop is also under pressure so true BP is higher. 200 is nothing for an engine, even in the Prius.

103F is the first temp target for engine shut off if not calling for heat. 154F is when the car considers itself at minimum operating temp to allow you access to all it's modes.

For those not familiar with them, the stages of warmup are described here. Gen3 warming up stages | PriusChat

 

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Even absent extra pressure, the common antifreeze coolant mixtures push the boiling point a dozen-ish degrees (F) higher than the boiling point of pure water.

 

Yes, a coolant mixture of 50% water and 50% ethylene glycol has a boiling point of 223 degrees at atmospheric pressure.
References for how this increases with pressure vary, showing as high as 3*F/psi. Truth is probably below that.
At one atmosphere of gauge pressure with 50/50 mix, you can probably count on a boiling point north of 250*F.

 

I would recommend an obd2 extender cable, and never worry about damaging the car’s obd2 port

 

It's actually Super easy to do a engine swap on the gen 3

Check out this thread.
Just Bought a 2012 For $700 with a Blown Head Gasket | Page 2 | PriusChat

And this Video On YouTube