Air conditioner blows warm when stopped

I have a 2005 Prius. I have been to 3 dealerships on 4 different occasions and have received 4 different answers. I'd rather know what is truly wrong before I pay to replace the entire system part by part. I'd appreciate any help with this.

The problem is that my air conditioner works well the first drive of the day or after many hours of sitting but blows warmer upon subsequent trips. With subsequent trips, it still tries cooling somewhat but blows only slightly cooler than the outside temperature. Even with the first trip, the temperature definitely blows warmer when I'm slowing or stopped. One example: at a long stop light, it went from blowing 58 degrees to 87 degrees (warmer than the outside temperature of 81 degrees). It will start cooling again a while after I start driving again. I have read that Prius compressors have electric motors so speed is not supposed to be an issue.

I really do not want to go through another hot summer without air, so I'd appreciate any info you can provide. Thanks!

 

Dealer #1 said it was the dirty cabin air filters. They were replaced and no change.
Dealer #2 Checked for leaks, none found. Said it was the condenser. They measured the temperature of the high pressure line right after the compressor. It measured 200 degrees. They measured the temperature of that same line right before the condenser, and it measured 100 or 150 degrees. The drop in temperature tells them that the condenser has a blockage. But, if they replace the condenser and it does not fix the problem, then they would also recommend replacing the compressor. (Shortly after this diagnosis, I found out from another Prius owner that they diagnosed and replaced the expansion valve, then the condenser because they gave him the same blockage story but no blockage was found when the condenser was cut open and inspected, then the compressor. I didn't trust them after that.)
Back to Dealer #1 - They said it was the compressor because it's noisy.
Dealer #3 Checked for leaks. Found the charge was low. Recharged it and said it was fine. It's not.

 

Should have added that Dealer #3 says the compressor is fine because it cycles just fine. Tech didn't notice a noise, although I hear a loud buzz when the AC is on.

 

I am in Denver.

When the temperature of the blowing air went from 58 degrees to 87 degrees, it was 81 degrees outside, I had the AC on max cold and high fan.

Today the outside temps were in the low 90s. I tried all combinations of fresh and recirculating, max cold and high fan, max cold and auto, 69 degrees and auto. I still had the problem with warm air blowing when slowing or stopped. The cooling worked less well when I used the car within only a couple hours of the last trip.

 

The outside air temps that the MFD shows are usually within a couple degrees of what other sources say. I have not noticed temps going up or down just sitting at a light. I do appreciate your feedback, and I will check the fans. It's easy enough to do, and it never hurts to check. Thanks!

 

Just received answer number 5 from dealer number 3. They say it's the expansion valve. The service adviser was not able to tell me why they believe that other than the tech said it's sticking open or closed. It's hard to part with lots of money when nobody agrees on what's wrong. I will check the radiator fans as suggested above when I get my car back, but any other info on whether the dealers' theories hold water would be greatly appreciated.

 

We checked the fans, and (unfortunately) they are blowing in the correct direction.

I got more information from the tech who said it's the expansion valve. He said the pressure on the low pressure side of the expansion valve is reading too high, and the pressure reading on the high pressure side of the expansion valve is too low. We asked if the reading fluctuated at all during his test, and he said no, they were quite consistent throughout the test. He said he has replaced numerous sticking expansion valves.

I think my next step is to write Toyota. I may not get a resolution to this, but at least they should know that their dealerships can't agree on a diagnosis and I do not know where to turn next.

 

It's my understanding that the expansion valve does not cost much, but the labor will. They were quoting $950. I have no idea what others charge for this.

I was quoted $2100 to replace the compressor by the first dealership. I believe a new condenser was between $800 and $900.

 

A friend also recommended going to a person who specializes in AC. I only found one business in the yellow pages. Hard to believe that there is only one AC business in the Denver area. Does anybody out there know of a good AC person?

 

Speaking of front end damage . . . my car was in a collision and the condenser had to be replaced. So my question is whether compressor oil needs to be added / replaced when the condenser is replaced? If so, and the repair shop used the wrong compressor oil, what problems would that cause?