While driving straight at highway speeds, I heard a loud whistling from the engine compartment and then saw a small amount of smoke come from the under the hood area. No lights came on dash. The A/C was on full blast at the time (its summer here in Louisiana). Shortly after this, I realized the A/C was blowing hot air. When I first started to try to diagnose the issue, I checked the AC diagnostic codes. 23 and 43 were displayed. Then I checked the pressure from the shrader valve in the low pressure side. Empty. Since it leaked out so quickly, I assumed a rock got kicked up under the car and punctured a rather large hole in the system somewhere. So I started to inspect all around the system to try and find a hole or leak. When I got to the compressor area, the joint where the low pressure hose side connects to the compressor, was visibly unattached to the compressor. It was come off due to the screw that goes into the compressor becoming stripped. At this point I figured the compressor shut down automatically because it detected a lack of refrigerant. I hoped that if I found a matching screw (which i did) and reconnected the hose to the compressor, stopping the leak (which I did) that at this point I could simply add the correct amount of refrigerant (the kind with no additives or oils) and that the compressor would fire back up and my AC would work beautifully again. After doing all this, the compressor did start right back up again. I saw movement again in the sight glass (with no bubbles). Yet after running the AC, its not blowing cold air. This is where I'm stumped. Any tips on what to check for at this point?
You didn't mention evacuating the system before adding the new refrigerant. You did do that, though, right? -Chap
You want to be a bit careful here. A rapid venting of the AC system normally entails a significant loss of lubricant. Very slow leaks usually result only in loss of refrigerant, but your description definitely falls under rapid venting. Refrigerant leaves no residue when it escapes and boils off. Is there any residue around the leak area? That would be indicative of lube loss.
Doesnt appear to be oily around the area where the hose became disconnected from the compressor. At this point, I may actually suck it up and take it to the dealer to have the system evacuated and recharged, filled with oil.
Did you also add some compressor oils? Considering that you had a leak, suggest that a significant %od the compressor oil must have evaporated too. You may need to vacuum the system of air using a vacuum pump.
Beyond may, you will need to do that. An A/C system can't have air in it; the air is "noncondensable" (at least, not at the temperatures and pressures the A/C needs to use) and if mixed in with the refrigerant, will get in the way of the "refrigerant cycle" that A/C depends on. When the tube came loose, the refrigerant got out, and air, also carrying moisture (another problem) got in. The system needs to be pumped out to a nearly true vacuum before putting refrigerant back in, enough vacuum to get almost all the air out, and for any water in the lines to boil at ambient temperature and be sucked out as well. Not every sort of vacuum pump can achieve a good enough vacuum; the ones A/C shops have are specialized and a bit pricey. Having the system hold the vacuum for a period of time after being pumped out also serves to verify that you've got any leaks fixed, before you put the refrigerant in. There is a component next to the condenser called the "drier" that contains a replaceable element. It has probably been exposed to enough moisture now that it should be replaced. And then, as others have suggested, there needs to be the right amount of ND-11 oil added to make up for whatever amount escaped. Then the new refrigerant can go in. -Chap
Thanks for taking the time to clear these things up. Since it sounds fairly necessary to use specialized equipment to properly service the Prius AC, I'm going to go ahead and have the dealer perform this job. It's a bummer that the Prius AC system is designed in such a way. This is my second Prius to have an AC related failure. And while I've had other parts fail on these cars, most of the other ones have been fairly straight forward to remedy or replace. Ah well. Gotta have AC in this Louisiana summer heat!
Well, there are some special things about Prius A/C, but hardly any of them were in what I just posted. That was pretty much all bog-standard A/C stuff: have to get the noncondensable gases and moisture out, ought to replace the drier if moisture got in, have to replace any oil that escaped, should hold vacuum before recharging to prove leak-free. Really the only Prius-specific thing in that whole list was the specific oil needed, ND-11. -Chap
Thanks for drawing my attention to this. Here we go! "The AC system MUST be vacuumed before refrigerant gets into the system".
That's the way to go. Post what they find/do, hopefully just a recharge is all that's needed. There's a few things I really don't want to do myself: 1. Recharge AC systems. 2. Tension garage door springs. 3. Get up on high and/or steeply sloped roofs.
Took it in today. Requested an evacuation and recharge. They said that my work was good and that there were no leaks. AC back to ice cold. Total bill $225.
