[Adobo_santos]

So my 2009 MO has started surging when the AC is on. I brought a recharge can at AutoZone and used the gage to check the pressure. everything was well within normal range. Today I took it to a local shop that did a vacuum and leak check and the AC was working fine after the removed some moisture. Once I got home and parked after a 8-10 min ride from the shop to home it started to surge again. could this be because where I live there has been high temps lately? should I do a coolant flush and see if that helps or check the battery. I believe the battery was brought in 2017. please help me out as i use this car to transport my mother to and from her doctors appointments. all help is much apricated.

 

[MuranoSL2003]

Is it your AC or the engine that is surging? Can you provide an explanation (or video) what you mean by surging?

 

[Adobo_santos]

Is it your AC or the engine that is surging? Can you provide an explanation (or video) what you mean by surging?

It's definitely the AC because after I turn it off the surging stops. If I just use fan mode it's perfectly fine. Only when the AC turned on or I come to a standstill in traffic or at a light does it continue to surge. I thought it was under or over changed system. When I brought it to the mechanic today they said it had low amount of freon. They did what they had to do it was working fine when I took off it was not until I got home and parked before turning off the car it started to surge again. As I stated earlier I believe that my battery was put in in 2017 so that means it's more than likely time to change that and I'm unsure if that could be causing it or could it be the engine temp causing the surge. I'm lost here as to what it can be.

 

[MuranoSL2003]

Explain the surging... Is it the fan changes speed when the AC is on? Or is it a sound? Does the AC still cool while it's surging?

 

[Adobo_santos]

Explain the surging... Is it the fan changes speed when the AC is on? Or is it a sound? Does the AC still cool while it's surging?

Fan stays the same speed when ac is on and yes it is still cooling when on. And it does still cool when surging. It will only stop if it's not in the on position. When the car is in motion it goes away when I come to stop or when parked and the AC is in the on position at any fan speed it begins to surge.

 

[MuranoSL2003]

Again, explain what you mean by surging... Is it a sound, like refrigerant or water gurgling, or something else?

 

[I need coffee]

Yeah, you need to be more specific about what you mean by "surging". For example, do you mean engine speed (RPMs) increases when you come to a stop at a traffic light?

 

[Adobo_santos]

Yeah, you need to be more specific about what you mean by "surging". For example, do you mean engine speed (RPMs) increases when you come to a stop at a traffic light?

Okay when I increase RPM and the AC is set to the highest fan speed the sound goes away now I did notice over the past couple days that when the temperatures outside were lowered the sound did not appear. Today as it was a little bit hotter 90°, the sound appeared also if I lower the fan speed of the AC the sound does stop and occurs less. I did try to record the sound but I am unable to capture it on my phone or any mics that I have.

 

[nitely]

Are you talking about the ac blower noise or engine noise? Sounds like blower noise?

 

[Philip]

Open the hood and watch the a/c compressor. You might be able to see if the motor is surging the same time the compressor is cycling off and on.