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Toyota Repair/A/C System Overfilled with Freon ?


Hi Ted,

I repaired my A/C but have some doubts:

1) The evaporator was leak so replaced it with new one, the mechanic do the vacuum and then filled with Freon but the AC was not blowing much cold air, I told him to add some more Freon but he told its enough after driving it will start cooling, but after driving also it doesn't cool that much as was before and at afternoon also not cooling properly.  I checked through the sight glass and found some foggy bubbles comes and goes, so I went to him and told to add some more Freon, first he refused and told it might have some other problem, but  I insist to add some Freon. I showed him the bubbles after seeing the bubbles he just added Freon for 2 seconds and closed the knob, after few minutes the bubbles again showed up, I told him and he added again some Freon for 2 seconds but told adding Freon may damage the compressor.

Now the bubbles are gone totally and the A/C is cooling very good at night almost chilling but I can hear some minor buzz sound when the A/C is working, I have doubt if the system is overfilled.

I kept eye on the sight glass for more than 10 minutes but I didn't see any bubble or liquid passing, the sight glass is pure clear, only when the clutch disconnects that time I can see some clear liquid for a 2 seconds and when the clutch engages again I see some bubbles and liquid move just one time for 2 seconds and then it clear all the working time. I kept my hand on the compressor and the connected pipes while working and tried to feel the buzz noise but nothing, when the bonnet is open the buzz noise can not hear the properly when the bonnet is open but only noticeable when inside the car.

Do I need to remove some Freon ?

2) The hot line pipe connected to the sight glass which goes to the evaporator has a little bent, do I need to replaced it, will it effect the cooling or restrict the movement of Freon.


The bubbles when the compressor clutch goes on and off is normal, if the pipe is not leaking and the bend is minimal there is no reason to replace it, not sure what the buzzing noise may be, if it's only with the a/c on it may be coming from the interior fan, check if the noise is there when using the fan only without a/c, it sounds like the system is not overfilled, if it was the compressor would shut of frequently due to the overpressure, so if it is working normally and cooling properly there is no need for concern at this time.  

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Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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