air conditioner doesn't work at high temps

Here are a few common AC problem areas:

• insufficient refrigerant in system due to leak
• compressor not working efficiently
• radiator fans not spinning when the air conditioner compressor is working; hence heat is not being dissipated from the condenser assembly

My guess is that the first problem area is the most likely. This can be identified by measuring the pressure developed in the low and high sides of the system. This can also be identified by looking at the sight glass on the high pressure side of the system when the AC is running. If you see bubbles this is proof that the refrigerant is low. If you see no bubbles then either the refrigerant is OK, or there may be too much refrigerant, or else it is non-existent.

Another qualitative check is to touch the low pressure side piping when the AC is running. It should be very cold and condensation should form on the pipes. If the piping is cold but the system is not performing, then there may be dirt in the condenser core or the expansion valve may be inoperative.

I suggest that you try another Toyota dealer's service dept to sort through these issues for you...

 

Ditto! The A/C should work fine with outside temps well into the 100s.

 

Driven mine many times at temps over 100 with absolutely no problem with the air conditioning. It could keep it at 70 degrees internally.

 

Yes, I have that problem too! It does not blow cool and if I try to push it the car overheats and either shuts down or the main emergency light comes on until I pull over and let the vehicle cool. I am trying to find others with the issue. I had mine into the dealer when it first presented the problem about 3 years ago. Then I learned to go without the AC until the heat wave we are currently experiencing this week. I have it at the dealer right now because it shut down on me on the way home. Of course they had no one to look at it when the problem was currently presenting itself and will probably not be able to "duplicate it" again tomorrow. It is really frustrating.

 

I'm experiencing the same issue. Will look at the sight gauge tomorrow. The outside air temp gauge doesn't provide an input to the A/C does it? It's evidently haywire, showing well over 100 degrees on a 75 degree day.

I thought the Prius was virtually immune from overheating. Not so?

 

Three recently registered forum members, all reporting the same rare problem. What do you think the odds of that are?

 

if it's over 100, my car can only maintain 80 or so inside. I keep it at 85 so it's won't killing itself while trying to keep the pack charged.

 

Some sort of under-bridge commune, maybe?

 

Any Prius owner who has a real air conditioning problem should take the necessary action to get it repaired as soon as possible. This is not just for your own comfort and safety; the car's electronics and traction battery longevity will benefit from maintenance of a moderate cabin air temperature.

For now I assume that all of the messages in this thread are posted in good faith:

- indigowahine's car might have a bad inverter coolant pump.
- Rob's car needs to have the outside air temp sensor checked as the wire harness connector may be loose or damaged; that sensor definitely provides a significant input to the air conditioning system.
- V8Cobrakid's car might need a refrigerant recharge; the sight glass in the high pressure line might help to show whether the refrigerant is low. If a recharge is required, then this implies a slow leak somewhere in the system which needs to be identified and fixed.

I have visited Nevada and Arizona in the summer when ambient temps are 110-120 degrees F, and the air conditioning has no trouble cooling the cabin air temp down to the low 70s F; colder than is comfortable. This is how the system should function in all Prius.

 

Patrick,

Thanks for the helpful response. Since I just purchased this vehicle, I have not yet had the warranty transferred. And since Toyota's warranty department is in Cedar Rapids, I wonder if they're dry enough yet to respond in a timely manner...

 

I guess pretty good. What is your point? Also how did this post contribute to thread?

 

The A/C pressure may be too high when the vehicle is hot. If air is moving accross the condesnor normally I would guess at a restriction. However a guess is all I can offer.

Any shop that services A/C should be able to diagnose this, (a hyrbid service center is prefered) by monitoring A/C system pressure.

 

Two additional questions:

How close should the outside air temp sensor be to the radiator?--mine appears to be within an inch.

I looked at the sight gauge and can see a gray-colored flow--an occasional small bubble, I believe. Is that sufficient evidence to believe it's low on R-134?

 

An inch is fine.

The sight glass has never been reliable IMO.

 

The ac stopped cooling in my 2004 on my last trip. The outside temp was about 85F. I haven't had a chance to trouble shoot the system, look at the sight gage yet. Until now it worked well at even higher temps.

 

Phoenix guy agrees 100%. Prius AC is as strong as any other car I've owned. Had symptoms sort of like what was described a while back, would seem cold if it was coolish outside, but no perceptible cooling when it was hot. Turned out to be a compressor failure in progress. It was the bearing failing, but it may have been stressed as my car is a salvage/rebuild front end accident. Worked fine for the first 6 months, then finally gave up the ghost. I was pretty impressed that our service writer got Toyota to pick up the ~$1000 compressor and only charged us $200 labor.

Rob

 

There have been a lot of trolls on the forum wasting peoples time lately, so don't be surprised if people are a little twitchy

Rob

 

People do tend to seek out these forums when they have a problem. Its also pretty common for people to have AC problems (on any car) when the weather is at its hottest. 2 of my 4 vehicles had AC failures so far this summer, and a 3rd is feeling week.

Not to say your reaction was totally unwarranted given the unusually high concentration of bridge dwellers that have been frequenting these parts lately.

Rob

 

If I haven't exhausted my welcome, more has happened since my previous posts.

On the way home this afternoon, in 80 degree weather, while on the offramp going about 55 mph, the high temp warning came on briefly. I turned off the A/C, and it went out within a few seconds. When I stopped, I couldn't detect any other indications of engine overheating. Could this have also represented something like an inverter overheating? I'm thinking all three events--A/C failing, outside air temp high, and high temp warning--are somehow related. Anyone with experience with these simultaneous issues? I'm about to call Toyota to see if they'll take pity on me before the warranty is transferred over to me.