air cond straining at +91 degrees,,

Are you using eco mode? Is the cabin air filter clogged?

 

The system should work at 91F. You need to have the dealer check it. How have you got it set up (Auto or manual, fan speed, etc.).

 

Usually everyone reports getting BETTER MPG's with Eco Mode on, this is odd.....

 

Okay... I know you have a Prius C.... but my regular Prius managed just fine with 4 people in it in the middle of Death Valley in July.

The a/c system is really quite capable in these cars from what I've both read and personally experienced. Get it checked out, park in shade, use window shades, open all the windows to expel built up heat to help, but hopefully you get the issue resolved.

Roland

 

Four hot people breathing inside a small car?

The C has a pretty good A/C, but it doesn't work miracles. Put it on recirculate, fan on high, roll up the windows, take it off ECO, and drive normally. That's about the best you can hope for. If the air coming out doesn't get cold in about four minutes, have it checked out.

I can see how being in ECO mode would allow for fewer mpgs - mashing the gas all the time due to the weak throttle response. Driver would have to also engage his own ECO mode setting for it to work properly with the automotive ECO setting.

 

I'm not sure tinting will help, might even make the car hotter.

 

Tinting helps. Keeps the sun out to stop the "global warming" effect. Nuclear winter...

 

My A/C worked fine when the outside temp was 97 degrees on a trip last year. (I got only 53 mpg on the highway that day)

 

my AC worked great the other day it was 97 it was just me in the car and I put the temp at 72 fan on high and in about 5 min it cooled off pretty well. the interior was still hot so the car will take an extra 20 min to cool off all the way. I was in eco mode that is where I leave it.

 

on a different note... my 06 prius , A/C doesnt blow cold air anymore.. The coolant control valve was bad, and i ran the car with that bad valve for a couple of months... just replaced the valve yesterday. The A/C still doesnt blow cold. I was hoping that replacing the valve would fix it, but what do i know ! No warning lights on the dashboard. anyone have any idea ? thank you so much...

 

The drier should have been changed also. You might check. The charge would have been removed to change the TxV....check that they put enough back in.

 

i changed the valve myself.. what do you mean by "the drier" or the "TxV" ? is that the coolant ?

 

Agreed that it should easily handle 91, especially with eco off and recirc on. If it doesn't you have mechanical failure hopefully under warranty.

 

When the valve is changed, the refrigerant charge needs to be removed using s vacuum pump. The drier removes moisture from the system, and should be changed anytime the system has been opened to the atmosphere. In addition, the system should be evacuated after the work is finished. These terms should be familiar to you if you feel qualified to change the valve.

 

At one time I was a mechanical (read AC-Heat-Exhaust-Plumbing) contractor. Held a Class A State license. Just telling you this to establish my 'bonifides' .

First, as everyone else says it should handle 91 degree ambient air. But, humidity also counts. If your ambient environment is humid you will always fill warmer than if it is not. This is because you cannot shed body heat as well in a high humidity environment as opposed to a low humidity one. So set your system to 'recirculate' to prevent humid outside air from entering the cabin. That way your AC will be pulling the moisture (humidity) out of dry air instead of humid (wet) air. Makes your system more efficient.

When you first power up the car and the AC it is OK to run your blower on high for a few minutes. You want to condition (that is where the word 'air conditioning' comes from and 'air conditioning' actually means heating or cooling or doing anything to 'condition' the air) the air in the car rapidly so as to bring the temperature and humidity down. But then, after 10 or 15 minutes, turn your fan to med. or slow. That is because the slower the air moves across the AC coils that remove the heat and humidity from the air passing thorough them the more heat and humidity will be removed.

The other consideration in air conditioning is the volume of the area one is conditioning. The larger the volume of the area the more conditioned air one needs to blow into the area to reach the desired temperature and humidity levels. If your C was as big as a bus you would run that fan on high for longer before turning it down. But, it is a C and not a Greyhound, so it is perfectly OK to reduce that fan speed after an initial period.

Less sun = less energy inside the vehicle = less heat inside the vehicle, always. I can not see any way that too much tinting could cause an increase in temperature. Add the sunscreen just like the other poster said but stay within legal limits for driving safety.

One more thing if you can stand it. In the normal residential unit the difference between the temp. of the air coming out of the AC unit at teh vents should be at least 12 degrees below the temp. of the air entering the unit through the return air filter. BUT, in a car, it should be at least 20 or 25 degrees different.

We call that the "Delta - T" (temperature difference) . The Delta-T is one measurement of the efficiency of your AC unit AND ALSO an indicator of problems with the AC unit. If the AC in your car is not obtaining a high enough Delta T under normal conditions then that indicates a systemic problem with your AC unit. Take a duct temperature gauge from any auto parts store, park your car in the shade, let it run for 15 minutes, and then check the temp of the air coming out of your vents and the temp of the air going back into your unit. You will usually find your return air ducts under the dash near middle. Look for a couple of plastic round ducts sticking out pointed at the floor. Feel for air flow, or use a feather, or whatever , but check those two temps and note the Delta T. Too little Delta T and you have problems. But be sure to do it on an average day temp wise and not the one or two days that are way off the curve one way or the other.

So sorry this took so long but I hope that if you understand some of how it works, and why, you can make a determination of what you need to do. This way you will know for yourself, and a mechanic will not be able to mislead you too much.

Or just take your car to a n AC mechanic you really know and trust and let him/her check it all out.

OK, final lesson, I promise... did you ever wonder where that puddle of water under your car comes from? That is the sum total of every water molecule (the 'humidity level) your AC pulled out of the air in your car and from the water your body evaporated into the car. We should start saving that water to drink before we run out of rain~!

Please email if you have any questions and thanks for being patient.

 

Excellent post but..........
Please post questions and comments HERE.
That is what a forum is for.

Did you mention NOT using recirc. the first few minutes with a window cracked........to expel the super-heated inside air ??
It's even better to driver a couple of miles with all the windows open and the AC off but the fan running.......if you can stand to do that.

 

I

I am not sure what you meant. Should I have posted directly to her post as a REPLY?

Thanks

 

No you are making this much too complicated.

I simply meant that asking for further discussion to be done via EMAIL kind of defeats the whole purpose of the forum.......because nobody else can see or participate in the discussion.