Prius 2010 overheating

Years ago I checked my temps at various places with a IR Temp. gun, I was totally amazed how cool the car ran. I got temps below 100 F. on a 2005. I can’t remember if I had the engine running, I believe I did, otherwise there would have been no sense in checking. By the way, that IR gun comes in handy.

 

So the inverter pump should definitely not be the problem?

 

If it's the engine that's overheating, then the inverter pump has an ironclad alibi. It has no part at all to play in that system.

If a person didn't know which system was overheating, they would need to check the readings to know which one had the problem.

An extraordinarily unlucky person could have both the engine cooling system and the inverter cooling system malfunctioning in the same car, but those would be two separate problems.

-Chap

 

A IR gun will isolate the problem, perhaps pinpoint. It will not show air in either system.

 

for air, you need an air Gun!

 

How much difference will it be in temp?

 

So far I have changed in order the water pump, thermostat, temperature sensor, radiator cap. Today I changed the water pump for the 2nd time and now everything is fine! Engine stays around 190f. I guess the 1st new water pump was defective.

 

Franken1313, I have the same problem as yours. Only on highway at high speed and load, the red light temperature is ON. At stand still, the engine heat up at 95 celsius then fans starts until 93 celsius. Then repeat. Bun at normal speed and load, the temp stays at 87-91 celsius.

 

can you use a lower temp thermostat for these cars i bin looking around and can not find one

 

not that i have read

 

The ICE will run to warm up until it gets to 100F then shut off unless you have the heater on in cold mornings.

The thermostat opens at 180F.

The coolant starts to boil at 212F.

I was told by Hybrid Pit 203F could mean a problem.

The engine will shut down and you will lose all power at 229F.

There is no thermostat that opens sooner than 180F.
I searched and searched and would have found it.

http://www.RedBullet.net

https://ProjectLithium.com/?ref=mG0GE

http://www.Pulstar.com

http://www.PlugOutPower.com
Use code 7373

http://www.hybridpit.com
use code azusa

 

One can come up with Fahrenheit numbers that are close, but I find the easiest ones to remember are the Celsius versions, since those are the ones the engineers used and programmed into the ECM, so they're nice round ones.

I don't believe I've seen the engine shut off after warming only to 100 ℉—that's only about 38 ℃, barely above where the electric boost elements in the heater cut out. When I'm parked with the car running, I'm used to seeing it cycle to keep the temperature above 50 ℃, generally shutting off when it hits 60 ℃. That's 122 to 140 ℉.

There's a bit of a surprise in what happens if you turn the HVAC off: the engine will run longer and seek a setpoint closer to its normal operating temperature around 80 ℃, as described in the Gen 3 on-hunkering thread.

The thermostat opening temperature of 80 to 85 ℃ could indeed be called 176 to 185 ℉.

212 ℉ is the boiling point for plain water at atmospheric pressure. It isn't the boiling point for SLLC: a 50% mixture of ethylene glycol and water has an atmospheric boiling point of 223 ℉ to 225 ℉ depending on where you look, so around 107 ℃. But ...

the coolant in the car doesn't stay at atmospheric pressure. The pressure cap on the system is rated 108 kPa, or about 15.7 psi. At that pressure, 50% glycol/water doesn't boil until around 267 ℉, or 131 ℃. (You'll get the red thermometer light at 120 ℃.)

The engine will shut down at 105 ℃ (221 ℉) if the ECM is reporting a water pump issue. That shutdown is a decision the ECM makes on its own, so even the power management control ECU gets a little surprised by it, and logs a P0A0F-206 "weird, engine won't start" code. It doesn't cut power to anything else in the car, though you are left with only battery propulsion and we all know how little of that is available in any Prius that isn't a Plug-In or a Prime.

If the ECM is not reporting any water pump problem, then it doesn't take any special action at 105 ℃, and you can reach and exceed that temperature without a shutdown. I'm not saying it's a good idea. The red thermometer will light up at 120 ℃. If there is a different automatic shutdown temperature for when there isn't a pump problem, the repair manual doesn't mention it and I've never experimented to find it.

 

If the "old" thermostat was working as designed, then replacing it with one that opens at a lower temperature won't have any significant affect. The thermostat should control the engine's MINIMUM operating temperature. When everything else is working correctly, then airflow over the radiator (ie, radiator fans or moving down the road) should control the maximum temperature.
When there is an "overheat" condition and the 'stat is open, then the problem is something else- lack of coolant or coolant flow, radiator can't transfer heat to the air (damaged or clogged fins), "too much heat" in the engine (such as restricted exhaust), or (combustion) gases in the cooling system (H/G).

Posted via the PriusChat mobile app.

 

Old thermostats can "fail" gradually. The rubber flange that seals can harden and fray, leading to less than complete sealing at any engine temp. And the wax component that gradually opens the valve as temp rises can change over time: open sooner, close later.

Come to think of it, this'd lead to over cooling.

It's interesting to suspend old and replacement thermostats in a pot of water and bring it up near boiling, just to see what you're changing.

 

i figured it out it was the egr cooler
as mush as i spent days cleaning it
out it still wasn't enough i put a new
egr cooler and all issues solved .i
hope this might help some body out !