Friend - I hope that it was found. For us, it was the hissing AC that did in our 07 SLT2. Seven repairs, where variously they could not find anything other than low coolant and filled it up. one time blamed on a bad schrader valve after the previous repair. Twice they replaced the dash controls. Hissing is the sound it makes to increase the pressure in the system, and as it gets lower and lower, the hissing will get more frequent. It got to be we could never know if some hissing was normal or not - because for two years there was always at least a little.Jayhawk said:I took my 2007 SLT, 62k, in to the dealer for the same issue. Loud hissing in dash when AC on. The dealer first said he could not hear it....then he said it was normal. I asked if the Freon was full and he said yes. I have had the car for 5 years. It was not hissing when I bought it and it had been getting louder/more persistent over time.
Trusting myself I took it to an independent shop. They reported .96lbs of r134 in system (spec is 2.32lbs). He was extremely intelligent and thought it sounded like the expansion valve trying to regulate the pressures. He replaced the Expansion Valve. It has been several days now and system is running great.
I have read others report this problem was solved by a Evaporator. In further research it appears that a new Expansion Valve is included with the replacement Evaporators. Leading me to believe that many people are paying for a whole core when in fact a valve is all that needs replaced.
I hope my luck holds, but one thing for certain is I will not be returning to my local dealer any time soon!!!
Thank you for your update. I'm experiencing the same issue. Taking it to the shop this week. Atleast I can tell them what to look for.Last Update from me.
It turns out the issue was a leaking evaporator core, and there was also low refrigerant. So there you go, 2016 Acadia has the same problem.
Please post again with the results of your trip to the dealer. It sounds like to me that it is not a question of if, but when, my Acadia will start doing this. I guess the bright side to this is that since both the front and rear evaporator cores are prone to failing prematurely, the total cost to fix both will easily exceed the cost of the extended bumper to bumper I bought. The negative side to this is that if GM hasn't spec'd better designed parts to prevent this expensive and unnecessary repair, then it is going to fail again and in my case, I will be stuck having to fix it. For the mechanically challenged, I would reasonably expect someone to be pissed off at the high repair cost.I just recently started having this hissing sound on my 2016 acadia slt. My AC blows warm air and the hissing comes and goes for like 30 seconds..I have the extended warranty, so I'm taking it to the dealership on Monday. So glad I read this comments.
I firmly believe the weak link in this system is the thermal expansion valve (TXV). They (GM) sell the TXV as an integral part of the evaporator as well as a separate part on most parts listings. It's beyond comprehension why engineers didn't design a firewall access to this ~$10 part to make a change easier to do. Some resourceful tech could probably find a way to do that and provide their customers less costly A/C system repairs....
Does anyone know why the front evaporator fails like it does? ...
Some of the things engineers have done over the years are beyond comprehension, and as a result, we the consumer end up paying the price. It is what it is. I'll deal with it if and when the problem comes up. I'll talk to my guy at my local dealership and see what he says.I firmly believe the weak link in this system is the thermal expansion valve (TXV). They (GM) sell the TXV as an integral part of the evaporator as well as a separate part on most parts listings. It's beyond comprehension why engineers didn't design a firewall access to this ~$10 part to make a change easier to do. Some resourceful tech could probably find a way to do that and provide their customers less costly repairs.