Scotty,
A Toyota dealer has told me the evaporator core in my 2007 Avalon is leaking and that it is a common problem on this model. (Really?!)
The car has ~110,000 miles, the AC system will not stay charged at all (a recent somewhat sudden failure). Toyota used leak detection fluid has been but I don't see any on the firewall evaporator core side, yes I used a UV light and tinted glasses. In fact the dye appears to have been spilled in several places so I really cannot determine the source.
My regular trusted independent mechanic cannot rule out the evaporator as a possible issue. But truthfully he admitted he doesn't want to do that kind of AC work.
The Toyota dealer gave an estimate of $1600 or more. I searched YouTube about the issue and yes it appears the entire dash board has to be removed. A job I don't have the time or desire to do and since this is my wife's daily driver, I need someone like Scotty to weigh in. Is there something obvious I have not checked?
I do my own mechanical work whenever possible and have many years experience doing so. I can service AC systems in homes and cars and can vacuum out the system, replace compressors etc. but this is "different".
I know it is a shot in the dark but please someone, let me know your thoughts.
-Ken
Use a refrigerant leak detector (the one that beeps and scotty used to check his teeth in a video LOL) It is not holding a charge at all?
I tried the leak detector initially. It was before I let the mechanic look at it. It seemed to be around the filler valve so I replaced the core on high and low side. Initially the leak was slow over several weeks then suddenly, it simply would not hold refrigerant at all. The last attempt for me checking it was August. After the Toyota dealer looked at it I have not revisited the issue with any enthusiasm if you know what I mean. We live in Alabama so AC is a necessity.
I suppose I can try again to find an absolute leak area. I was just floored at the Toyota guy saying "oh it is a common problem with this model" If so, was there a recall? How can I check that?
you will never find a recall on an air conditioning issue. The recall process is for safety related issues only.
That said, there are six recalls on the 07 Avalon, it's worth running your VIN by the dealer to see that they're all done. There may be a service bulletin that you could search for. Also look for complaints at consumer reports to see if it's common. https://www.nhtsa.gov/vehicle/2007/TOYOTA/AVALON
Most electronic leak detectors will alert on nitrogen as well as R134a if you have some. You can over charge with nitrogen (very cheap) to check for leaks. Stick the probe in the condensate drain (direct connection to evap box) or in the discharge vent nearest the evap box with the engine & blower OFF. If gas is detected in drain or vents, it is 99% probability the evaporator has corroded & must be replaced along with new accumulator, system evac & recharge.
Evaporator leaks are common on R134a systems because acids are formed when moisture gets into the system that can eat tiny holes in metal parts. (It's impossible to keep all moisture out and on an old car the drier is probably not doing much.) Unfortunately a lot of cars seem to be assembled around the HVAC system, requiring enormous amounts of labor to replace evaporator, heater core, or blower motor.
Do not be tempted to use AC sealers. They can further damage your AC system, or damage test equipment, when they solidify in the wrong places.
