Help Diagnosing AC problem...

Try this thread from 3prongpaul who does Prius repairs in Colorado and see if this helps.

HVAC air control directional settings not working | PriusChat

 

Probably no maintenance has ever been done on the ac system. Here's the minimum:

1----Replace or check cabin filter monthly

2----At leas once a year have the evap box under the dash cleaned by injecting ac cleaner foam back up the condensate drip hose. Dealer sells the 2 can kit but and aftermarket can is available from Amazon called Kool it.
Dealer charges $100 to do this. Keeps the evap coil clear and condensate hose from clogging and removes mold from the coil. A big problem for Prius that tends to get smelly from ac e-coil box mold.

3----The front ac condenser needs to be cleaned at least once a year. Remove the top plastic engine cover. You now have good access to the condenser. Hose it off. Using a can of pressurized foamy ac condenser cleaner available at Home Depot hose down the condenser with that cleaner. Let sit then rinse off. Gently scrub out any hardened dirt and bugs without damaging the fins. After good cleaning do close inspection looking for an fod damage to the fins. This alone will increase cooling efficiency about 20%.

Basically the same stuff you should be doing to your home ac system.

 

Your welcome! This is one of those cars that responds well to any attention you give her. Great little car.

And please steal away....lol....

 

Hey Jd is that the door that makes the groaning sound too?

 

I am not sure of your question. I just remember seeing this post.

 

It sounds to me that your evaporator is freezing up--to the point of restricting air flow. When you turned it off for several hours, the ice melted, and it would work properly again.
I'd start by checking for the proper amount of freon, and for proper drainage of condensed water from the evaporator.

 

I would imagine the dealer checked this, but are the cooling fans working on the radiator/condenser assembly with the A/C on?

 

pbarber, usually the evaporator itself doesn't get "dirt clogged" (unless the cabin filter is removed to allow debris to enter), but there may be some accumulated debris around the drain hole, but I doubt that is the cause of your problem.
The expansion valve "sprays" freon into the large area of the evaporator. The freon goes from a high pressure (before the expansion valve) to a low pressure (in evaporator). This process of lowering the freon pressure causes the temperature of the freon to drop accordingly. Blow air through the fins of the evaporator, and you have air conditioning. Something in your a/c system is either allowing or causing the freon in the evaporator to become so cold, that it is freezing the condensed water that is created from normal operation. You say that the air flow does return to normal. If so, that tells me that the evaporator is not clogged with debris.
Hopefully someone, with a better knowledge of the operation of today's Prius, will be able to help us as to what specifically would allow the freezing in the evaporator.

 

No expert here. To me it sounds like the system simply froze up which the OP suspects. You might be a low on Freon. Gages would be necessary to confirm this. You can also check the sight glass in the system. I think the problem stems from running it at 68 in recirc mode. Even on the hottest day here in Texas I have never ran the system lower than 72 in either mode. At 68, it should be like a icebox in there if the system is running normally.

If you have trouble again, get a reputable A/C guy who knows the Prius system to check it out. Prius is unique in a couple of areas on the A/C hence whoever does the work should be familiar with the system.

Best of luck to you.

 

Glad I could help. The Kool It tip was from anther poster excellent find on Amazon. Very good to know the rubber hose interfaced good with the Prius drip hose. The dealer wants $25 plus tax for the 2 can kit. One can of that kit is worthless as its just really strong old lady perfume. How much was the Kool It please?

I do mine once a year...its worth it just to keep the drip hose unclogged. For some odd reason it smells less and less as the car gets older after a few of these treatments.

Now try the front condenser cleaner lol...that really makes a difference in how cold it gets especially with the car sitting.

And here's your first like!

 

A small comment on the above posts: no "Freon" in anything now. That was a trade name for R-12 refrigerant, phased out last century. Prius uses R-135a like the rest of the cars on the road.

 

$11.97 is excellent. I'm on that next go.

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Whoopee!

 

$10.99 at the moment for Kool-it at amazon, Amazon.com: Kool-It 96030 Evaporator and Heater Foam Cleaner: Automotive

I also saw this one, Amazon.com: einszett 961105 Klima Cleaner Professional - 8.5 oz: Automotive . $15.50 for a larger bottle. Has a lot more reviews on amazon than the kool it.

Locally, I found something called "CARQUEST Chemicals Odor-Out A/C Cleaner - Spray can with hose, which directs the cleaner deep into A/C vents, 8 oz can, sold by" for $6.49. That's all it says about it. I wonder how it compares to the other ones?