Gen 3 A/C

Fantastic. Thanks, Mendel. Yeah, I'd let the pros do it too, even though I have A/C experience with mini splits using old fashioned freon down in Honduras. It's still nice to know what to look for.

I'll have to re-check later. But my initial check makes me think it's a little low. Getting some bubbles and not as much temperature difference as I'd expect between the high and low sides. Not is there as much temperature difference as there was last summer between ambient air and the air coming out the vents. If I'd waited for your additional info, I could have checked for foam when I shut it off. Will try that tomorrow. It's plugged in with the timer set now. Don't feel like messing with it.

 

The AC system is a vacuum tight sealed system. So whoever told you that is false. If there is water in the system, it’ll rust from inside out. The only thing inside the AC system is Freon and a small amount of refrigerant oil.

 

The service writer used the expression "sealed system" talking with me. I suspect a slow leak, maybe from the car sitting for 15 months when new, and/or our ongoing very sporadic use. I've read this can lead to not enough oil circulation, seals drying out.

 

Only way to tell is a leak test. Rubber seals shouldn’t deterorate that quick, even if it’s the AC system.

 

I thought that it can somehow cumulate moisture even when its sealed. Anyway main reason is that freon is getting low if AC wont blow so cool air anymore after years, somehow even it can escape system little by little. And if AC then is used, it runs dry and can cause bigger failure.
Servicing AC at every 2-3 years cannot be waste of money, more waste is to push it to the limit.

 

It is good to run the A/C every month or two to redistribute the oils and keep moving parts lubricated.

As for moisture, there is way more pressure inside the system than outside, so moisture can't get in unless the system is opened and then recharged without using a vacuum pump first to remove the moisture before recharging.

 

Well I can tell you with Pearl S when you press "Auto" the A/C green light comes on. When you turn the fan on the A/C green light comes on. It seems to be the "default".
Now, if I turn on the fan, then press the A/C button to turn off the A/C (cooling) it stays off even when the car is shut down and then restarted, until I press the "Auto" button. Then it returns to the "default" condition (A/C on but cooling only when needed for the set temp).

But here we have cryogenically cooled outside air, so most of the time fan only is just fine.

I suspect the original poster has an A/C system problem. Fuse or out of coolant due to a leak (the condenser is exposed to rocks unless you install mesh behind the grill).

 

From the responses, I'm getting the sense that 2010~2011, invoking Auto didn't turn on AC, but from 2012 onward it does?

 

Well, here's a thing, from the list of dealer- (Techstream-)customizable settings in the 2010 Repair Manual.

I'd guess we have people reporting different behavior because that second setting is set differently in their cars.

It's quite possible I set mine to Manual back when I bought the car (because that's the way I would have liked it) and then forgot doing so.

Mine must still have the Air Inlet Mode set to Automatic ... I'm getting tired of setting it back to Fresh after every time I turn on the A/C. Guess I've got another setting to change....

-Chap

 

Nice!! I didn't know about those options. I might change the air inlet mode on mine to manual. I defaults to recirc. Most times, it's way hotter inside the car than outside when I start up. I'd rather take 90° outside air and chill it to about 70° than take the 115° inside air and chill it to about 95°. Once it's cooler inside than outside, then switch to recirc.

 

Rats! My screen has everything BUT the air inlet mode. Using version 10.30.29.

 

good question.

 

Indeed! But, we'll carry on with or without the OP.

 

wouldn't have it any other way, but there's always that nagging itch to try to help the o/p.

 

So the default is to have AC come on when Auto is pushed. Ours has never done that, and I've had the battery disconnected various times, for brake work, fwiw. Maybe varies by build-date, ours is August 2009, and Canadian spec. obviously.

It does not do that switch to recirc either, when AC button is pushed, at least I can't recall it doing that. Though I don't use AC that much, so might have missed it.

 

It is possible for an ac system to leak (slow leak), rock hitting condensor in front or not running ac will dry out the green rubber "o" rings in the system. Ac leaks accumulates oil around the failure in most cases. It is a good idea to cycle the ac even in the cold months. Oil from the compressor cycles through the system to prevent "o" ring failure. If air enters the sealed system. Moisture in this air can create acid that will deteriorate parts causing a failure. The ac system in the prius is Extremely expensive to fix. You will have sticker shock from the dealer. I replaced a compressor(used), condensor/dryer and recharged the system with r134a and new hybrid compressor oil for 166$ and my time. If the ac system running at <50% you may see some bubbles in the site glass and 100% should be clear. Compressor's can fail early if not properly running the correct amount of refrigerant.

 

Hopefully just replacing a seal or two is cheaper, if that's our problem.

 

Seals are cheap to replace but a full refrigerant recovery is needed along with a vacuum pulled on the system for 30~45 min before refrigerant is pumped back into the system. Some refrigerant has a stop leak/seal conditioners for ac systems but not sure if it is hybrid compressor safe? Hybrid compressor oil level would also be unknown due to leak, so pulling the compressor and adding oil will also be in order. If a tech did this incorrectly, who knows how long it would last. Not having ac is dangerous to drive in rainy or humid cold conditions due to not be a able to see from the inside of the car.

 

Yep, that’s why I don’t deal with AC and just bring it to a shop since they have a machine for it lol. I don’t trust those AC in a can.

 

Mine had been struggling to keep up when the outside temp is over 90. There were bubbles in the sight glass, so I assumed the freon was low. In fact, at one point it acted like it had iced up (almost no cooling at all) but I didn't look to see.

A good friend is the best A/C and refrigeration guy I know, but it's residential and commercial. We couldn't be sure his gauges had never been used with a PAG lubed system, so I decided to not risk having him help me and possibly contaminate my system.

This morning I took it to Toyota. They recovered 5.8 ounces of freon and put back in 18.24. Yup, it was low all right. Temperature at the vent went fro 57° to 39°. He didn't find any leaks, so he injected some dye so that if it goes low again the leak will be easier to spot. Time will tell.

Since the A/C won't need to work as hard, I wonder if there will be a discernible difference in mileage.