I bought this 2004 Prius in 2010 with 104K miles. Now at 117K. When outside temp goes to 86 F or above, the a/c blows warm air. If I stop A/C for a while, and restart it, it will blow some "cold" air for 10 seconds, then back to "warm" again. at below 82F it seems work normally, although I never felt "cold" enough like my other car Lexus LS 400 1998. My mechanics found (using his diagnostic device) that the thermometer temp measure indicate as 28F when outside was at 90F. He can not figure it out. Is it possible that temp sensor (thermometer) gone bad? Or it is just a loose connection which might cause the resistance value change? He added enough refrigerate fluid for the car. I noticed in glove box there are evidence of glue used. I suspect that the car had some body damage on right side and being fixed. Anyway, the a/c problem so far happens consistently at around this temp. I have no any other problem on this beautiful car. Here is my general usage of the car: I commute 124 miles round trip daily. Live near Chicago, winter mpg 50, summer 58. Allen
What type of refrigerant fluid did he use? It's not the generic stuff is it? Are your radiator fans working (blowing air inward)? Be sure that they're not reversed.
Bob, Thanks for reply. I am surprised to know that there is another type of refrigerant...I think I checked Prius menu and found the right type and only type sells in Walmart. The fan works strong and normal.
I suggest that you take your car to your local Toyota dealer and see if they can figure out your car's AC issues. Maybe a temp sensor is bad, or maybe the AC amplifier is having a problem. The refrigerant by itself is not an issue. The issue would be if you used refrigerant mixed with generic compressor oil. The Prius AC system uses a special compressor oil which does not conduct electricity.
Amplifying Patrick's point: if refrigerant containing the wrong oil was used it will destroy the compressor. A non-Toyota mechanic may not know this. Find out, and if so don't use the A/C until you can get it to a Toyota shop.
Thank you all who tried to help. This issue is resolved. I went to Arlington Heights Toyota dealer in IL, they told me the refrigerant amount should be 1.06 LB, but my car loaded 1.5 LB. Overloading is the cause of lost cold air. They simply recycled that .5 LB, and now the AC works like dream! $60 is all I paid.
Did mention to them the type of refridgerant you used? They might have assumed it to be OEM and not checked. I would still follow up to make sure it is non-conductive.
I had the local non-Toyota shop check if the refrigerant was down - they said they added 1/4 lb of "standard 1394a" refrigerant. Now the AC shuts off after 5-10 minutes. Is this likely to be due to use of a refrigerant with conducting compressor oil? Taking it to the Toyota dealer today....
Some A/C info for Gen2 & 3 Prius cars. The compressor is a scroll type electrically driven unit,three phase in nature, driven by the DC-DC converter & controlled by the HVAC ECM. The refigerant is R134a BUT the lubrication is by POE oil NOT PAG oil as used in most vehicles. The moisture saturation of POE oil inherent in A/C systems is far less than PAG and ensures that you do not get internal current short down within the compressor and a localized failure with a code.Such a condition will cause a shut down in extreme cases. In any case a corner A/C shop may not be aware of these requirements, I use a dedicated A/C recovery/charge machine to ensure no mixing of oils takes place when working with Hybrids. This ensures a professional repair every time. Regards Actros
