# Extreme heat and a Prius



## Nik333 (Mar 1, 2015)

My 2010 Prius Hybrid seems to have a hard time with high temps like 106F - 112F. It also had a hard time with relative cold.
Frequently, it says the engine is hot. It is hot!😊 it's the yellow warning light. I have been checking fluids, but, it goes away when it cools down, outside.

Also, I'm just curious if a smaller amount of gasoline can be made gaseous by heat & not be utilized properly. I ran out of gas recently and the icon that shows what I think is my total energy available, (Hybrid) showed full, but, still ran out of gas. I've always been able to trust that icon. If it was full I could drive a ways. ( I think a ways is Appalachian English for a fair way.)


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## ukrkoz (Dec 31, 2010)

You do not have gas meter in this picture. You have separate gas gauge and please, follow that. Light comes up, you have 2 gallons left. There is no such thing as "total energy" meter.
If you run out of gas, you will be able to drive in EV mode for maybe a mile, maybe a bit more downhill, then your car is DEAD, as in - dead. Towed and paid to dealer to recharge hybrid battery.
There is no trophy for running out of gas!
As of the "hot engine"? Do cooling fans come up? How do you think people drive Prii in deserts, where it's 120 all the time? If you refer to hybrid system overheating, clean hybrid battery fan and air filter/ducts.


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## quatsch (Feb 4, 2021)

Vapor lock affecting your fuel supply?


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## Nik333 (Mar 1, 2015)

ukrkoz said:


> . . .then your car is DEAD, as in - dead. Towed and paid to dealer to recharge hybrid battery.
> There is no trophy for running out of gas!


The battery has never died, requiring recharging, in 5 yrs. It goes quite a ways - miles. My Auto Insurance says running out of gas happens a lot to Prius owners. it happened a lot at first, but, almost never, now. That's why I thought this was related to the heat. I read that there's a vent on the right side of the back R seat. It may be covered, I'll have to check in the morning.


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## Nik333 (Mar 1, 2015)

quatsch said:


> Vapor lock affecting your fuel supply?


Related to the heat?


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## Half-fast eddie (Sep 19, 2020)

Nik333 said:


> Related to the heat?


Yes. Back in the day, fuel line vapor lock was a fairly common thing. The gas in the fuel line would get too hot, basically form a large bubble, and prevent the liquid gas from flowing. I would be surprised if that happens in a modern car, but it could. 

I have always heard that running out of gas is a bad situation in a hybrid. Problem is, you then think you can go just one more mile … one more then i’ll stop … ok just one more … and then if you drain the battery you have destroyed it.


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## ukrkoz (Dec 31, 2010)

Have at it....



what happens if prius runs out of gas - Google Search


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## Oso954 (Jun 23, 2012)

Regarding the overheating, there are many things to be checked and I’m not sure you can do all of them. I think a good mechanic that works on Prius or the dealer might be the best bet. You can waste a lot of money if you just start changing parts, chasing the problem.

The one thing you might try is looking for obstructions between the radiator fins. You can do it from the front by shining a flashlight on the fins, or by a flashlight on the engine side while you look from the front. Bugs and dust can severely restrict the airflow.

You can attempt to wash it out with a garden Hose from the engine side so you are blowing the debris back out the way it came in. I dont know the actual access in a Prius for doing this. On some vehicles, you must pull the radiator to do a good job of it.

When you need to add fluid to the radiator do you just add water or is it a water coolant mix?
Also have you been changing coolant or at minimum adding an anti rust fluid to it every year or so?

Too much water promotes rust/scale as does the anti rust deteriorating over time. Depending scale buildup, it can be back flushed out of the system, or in the more serious cases it may require removing the radiator/servicing it (often called a boil out) or total replacement of the radiator.


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## Nik333 (Mar 1, 2015)

Oso954 said:


> Regarding the overheating,


It hasn't done it again since the first two days. I did put it in the shade after that, before it got so hot, but, the next day I didn't. It's been 115F on several days.
I had an appt with a mechanic but canceled that when it didn't overheat. He was pretty booked..

I remember the car revved a lot the first day, at rest, with the A/C on. I may not be cranking down the A/C as much, now, especially the fan, which is now set on a lower setting. I have a bad indulgence of driving with the windows slightly down & the A/C on. I just like the airflow. I know the A/C recirculates the air in the car, so now I just close the windows completely & it doesn't have to work so hard.

Every computer I have does poorly with heat, so maybe the Prius is not an exception.

It seems to be the heater or A/C that stresses the car the most. I wonder how Priuses do in Canada?


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## quatsch (Feb 4, 2021)

There is an outside design limit temperature for HVAC units and I'm sure there is one for vehicles.

They may not change the hardware for this, but there may be software changes depending on the cold climes and the hot climes.


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