Normal Operating Water Temp

13.7v and 13.8v are what my Gen2 read. My Water temp was near 185F

In the new v wagon, I see 14.4v and 191F

 

Does your heater run hot? I've never seen temps over 205 (and I run a high temp thermostat) , even in the summer, except for the times I've drained the engine coolant, and had an air pocket. If over time you still see the high temps, I might consider a new thermostat, but these cars do take time for all the air to purge from the system.

 

220? That's not good. Is coolant at full line?

Really shouldn't get any hotter than the temp opening of the thermostat which is usually 195 for a Prius. My Gen II never gets any hotter than 200 even on blistering day and stays close to the 195.

If air in coolant you will hear water sloshing sounds under dash with heat on. Do you have heat? If air trapped you may not have good heat?

Was your car a front end hit rebuild? Not sure? Go to a dealer and have them pull vin maintenance records.

If me I would check operation of the electric fans on the rad. One is ac assist the other is rad. At the 220 temp pull over turn off ac and leave car in ready and see if rad fan is on. 220 the motor is really hot. Fan must be on. Make sure fan is pulling air through the rad and not on backwards. Then turn on ac full blast and confirm ac assist fan is on. Both fans should be on.

If fans ok check front of ac condenser coil that is mounted in front of rad. Make sure its clean and not bug clogged.
Once a year I spray coil cleaner on the that coil (blue spray can from HD) and hose off. Should be shiny clean.

 

A simple test for checking if the fans are in reverse positions is that when driving the outside air temperature readings go haywire as the fans blow hot air on the sensor.

John (Bitprius).

 

Good one John. Like it.

 

30 years ago I bought a Corvette and the guy just had the engine rebuilt and just installed it back in himself.
He said it ran fine on the hi way but when it sits at lights it spikes the temp gauge.
It sounded perfect to me.

I had been working on 350's a long time and knew this engine. I looked at it for 5 minutes and saw he had the
mechanical fan on backwards.

I beat him up good on the price. Never told him. I always check the fans now out of habit.

 

Do you have cabin heat?

 

Perplexing. That requires good coolant flow from engine through heat exchange coil under dash. Impossible to have cabin heat and cold bottom hose. Or at least I have never seen that before.

 

I suggest that you obtain a handheld infrared instant thermometer and use that on the cylinder head and radiator hoses to verify the temp readings you are getting from your ScanGauge. I would agree that 185 degrees F is normal operating temperature.

If you confirm that the operating temp is much higher and you have also confirmed that the radiator fans are working correctly (i.e., sucking air from the radiator and not blowing air forward into the radiator) then maybe the thermostat needs to be replaced. Turn on the AC compressor to get the fans to operate.

 

Patrick's idea of checking the temperature with another thermometer is a good one, but one other item not mentioned so far is the temperature transmitter "this could be giving out incorrect information" it is easy to change and not expensive to eliminate this as a possibility.

John (Britprius)

 

Yes Sensor. Because at 220 the coolant is boiling. Past boiling. And you will see steam. And damage quickly ensues.

 

Did you program the scan-guage to show engine temp/coolant temp yourself?
Or did you use the scanguage buit in function Wth (water temp farenheight).
The reason I ask my scanguage (older version) has preprogrammed Wth, I've seen other
programming to read coolant temp & engine temp using the scanguage user programming feature.
I tried the user programmable types on the internet to see what the difference is and I still don't know..
However some for the math conversion to change celsius to farenheight are way off on some of the
user programmable functions found on the internet.. If you using the preprogrammed function temp should be right..

one of the user programmable function listed on the internet for coolant temperature interfeered with the built in
scanguages rpm reading on my 2009 prius with scanguage. it showed 500 rpm while driving on the freeway at 65mph
for minutes at a time (stuck at 500 regardless speed changes) I deselected coolant temp user program and rpm reading has been
fine eversince....

I would think a legitimate 220 engine/coolant temp would light dash indicator and start radiator fans..

Hope this helps

 

Have used a scan-guage on a 2005 gen 2 for years, stat opens at 199F and with temps above 20F temp will sit at 184F, highway travel with temps subzero i've seen 181F with no grill blocking.

 

It's a long shot, but worth mentioning. If the thermostat is stuck closed, or there's some blockage in the engine, you won't see high temps at the radiator hoses. I'd trust the temp sensor over what I'm reading at the radiator...

 

Not unless there is something wrong with your cooling system.

Pressurized systems and increased boiling point from using coolant instead of straight water give typical boiling points of around 255F.