Hi all,

I recently had the evaporator coil replaced in my 05 4Runner Limited because it was leaking.

Since I got it back, their is a weird sound coming from behind the dash. It sounds like someone taking a deep breath every 8-9 seconds. It's like a 5 second intake sound, then a pause, then repeat.

It only happens when the AC is on, and it is continuous. I hear it very plainly from the vents, and when I put my head down by the passenger floorboard (near where the evaporator is located). I don't hear it as much by the driver floorboard.

I'll be taking it back to the shop to have then look at it, but if anyone knows what can cause this, it'd be nice to have that information ahead of time.

Thanks for looking.

ANY LEADS, A Pal has similar problem

I have been told a couple of times before that the compressor is on its last legs, but it has kept working. When I took it back to the shop that did the work, he said it was the compressor kicking on and off, and that the noise was an indicator that the compressor needs to be replaced.

I haven't been able to find any information to confirm or deny that, so for now I guess I'm just living with it, and glad to have working AC.

Did his start after work was done, or just out of nowhere?

Ok I have this same exact problem with my 06 Limited V8. Just had same work done and now the breathing sound. I've read elsewhere it's the expansion vave opening every 7 seconds when the compressor kicks on.

And that what you are hearing is the refrigerant expanding into the evaporator everytime the compressor cycles on. So it's in indication of slightly low refrigerant, add a couple of ounces and it will most likely go away.

Just repeating what I read, I don't know jack about air conditioning systems. I'm going to back to my mechanic tomorrow and suggest this.

Anyone else?

Not sure if our trucks have a true expansion valve or an orifice tube.

Thanks for the tip, Hkwoof. Have you given it a try yet?

Here we are 4 years later and my wheezing compressor is still going strong, so I'm glad I didn't pay to replace it.

I will probably try adding a little coolant soon.

Did yours start out of the blue or had some work been done?

Mine does this and has done this since november when I bought it. The ac stopped blowing cold a month or so ago and I did one of those charge in a can things from an auto part store and it immediately got colder and started working properly. However the noise still stayed. I plan to get the AC professionally evacuated and then recharged with the correct refrigerant amount and oil but I haven't done that just yet.

Evaporator is a big expensive job. Behind the glove box somewhere. If you get wet carpet, it's a clogged drain line. There's a tube that comes into the engine bay that can be cleaned out with compressed air.

I was lucky. Replaced the AC compressor with a new $190 compressor on Amazon (Denso), and she's been cooling good (but not like when new) for a year - right through the summers.

Can't expect the OEM 13 year old compressor to last forever.

Tom / Nassau, Bahamas

Summary: mechanic said not low on refrigerant still have the problem

You likely need a new expansion valve. They make a puffing air noise like that, its opening and closing that you're hearing when the pressure changes inside. Expansion valve is located with the evap core.

Anyone else?

I have the same exact problem and have had it since i bough my 4R. Since then I have changed the expansion valve and the condenser with no change in that sound. I did notice though that the system required more freon then spec which does indicate a weak compressor. With that being said i just installed a new compressor but i cant get the clutch to engage. Its gonna be cold from here on out so i may not know if it solves the problem until spring

I’m having the same issue, I was told that it may be the blower motor. I ordered one and will be replacing it hopefully next weekend.
I’ll let you guys know how it goes.

I'm no mechanic but blower motor doesn't seem to fit the symptoms. Any one else? Just to reiterate, I had my leaking evaporator core replaced and have this breathing sound afterwards.