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AC pressure release valve 2004 Deville

7051 Views 9 Replies 3 Participants Last post by  Ranger
Okay, so I was pulling into St Louis a week or so ago after a long trip from St Roberts Missouri and as soon as I take off after stopping at the first stop light I encounter a medium sized puff of white smoke comes out from the front of my hood. Then my AC suddenly quits. I pulled over to check to see if I was loosing coolant and I wasn't. All I heard was a hissing noise. I continued on afterwards. After going inside the St Louis arch(which was why I was stopping in St Louis), I left and then proceeded back home to Michigan. The day after I got back to Michigan I took the car into Tuffy so they could look at my AC system. They couldn't find anything wrong with it and determined that refrigerant for the AC was released through my pressure release valve because they found UV dye all over my radiator. I purchased a can of refrigerant to replace what was lost but I have not put it in yet. Does anyone know what could cause the issue with the pressure release valve releasing my refrigerant and if it will happen again if I attempt to refill it? I am considering taking it into my dealer to see if they can determine what caused the problem, but I would rather avoid doing this.

Edit: I tried adding more refrigerant anyway, as I am impatient, ended up wasting the can. It began to leak out through the pressure release valve after I started recharging it.
1 - 4 of 10 Posts
You could just be low on refrigerant. If the system is not cooling properly, it can over pressurize.
Check the basics. Is the condenser clear of dead bugs? Might want to blow it out with compressed air and then flush it with water.
Is the upper radiator sight shield and the lower air deflector in place?
Are the A/C inlet & outlet pipes on the firewall the same (cold) temperature? If not, you may be low on refrigerant.
"White smoke" out the exhaust? Sounds like steam. It shouldn't be condensation at 54 degrees, but perhaps coolant? Are you using coolant or overheating? Is this the first time that has occurred?

As for the A/C, if you had zero pressure it had a bad leak and that was confirmed by hissing noise and pressure drop during the recharge.
I did a little bit more research into AC systems on google and some have a plug that just one time opens to release pressure. Its possible this occurred. And it can sometimes be caused by the system getting too hot.
That's what I was getting at in post #2.

Anything out the exhaust is totally unrelated to the A/C system.
1 - 4 of 10 Posts
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