jsheehan

I noticed about a week ago that whenever I have the air conditioning on (as in the AC light is on, not when I just have air blowing but no AC) that there is a noise coming from under the hood. The noise can be described as sort of a pfftt. It sounds like the escaping of air from somewhere, and the pfft only lasts for a spilt second or so. The sound isn't constant and only happens intermitently. I just wanted to post on here and ask for people's opinions on what the trouble might be before I took it in to the dealer to have them look at it.

Grimlock

It's not the AC. It's the blow-off valve from the turbo. Perfectly normal.

Seriously, haven't noticed anything like that on mine.

Zodiac

Ive heard this same noise in other cars before, but never in this one.. I always just assumed it was the vents opening up and pullin in more air or some such?

jsheehan

I don't think that is it, as it is pretty loud. not that loud inside the car, but when you get outside and open the hood it is pretty loud. I can't pinpoint where it is coming from though.

EleanorsMine

thats cause these 05 vents are horrid horrid!
Too much air blowing on me makes me something something.

Super Snake

I have the same sound in my 2000 Mustang...im guessing its normal

Super Snake

I have the same sound in my 2000 Mustang...im guessing its normal

Super Snake

sorry for the double post haha

sviper

Yeah had the same thing happen. took it to the dealer and told me that it was the clutch engaging and that it will not or should not go away at all. I now don’t even notice it any more.

Caromo

I noticed this noise yesterday. Your description is exactly as mine. You can reproduce the noise turning on and off the A/C. Actually I could find the device making the noise, it is the A/C compressor, it goes on and off, and every time it does it maked that horrible "pfftt" noise. I just don't know if it is normal, it is loud and really bothers me. Any one else with the same issue?

PottyScotty

I just got mine back from the dealer and had them check on the a/c too while the car was there (same sounds on mine). They said it was normal and it was just the a/c clutch engaging and disengaging. It happens more frequently when the fan speed is set low than when it is set higher. I posted this in the "laundry list of issues" too.

openminds

Having the fan on low decreases the amount of air flowing over the AC condensor therefor allowing it to reach it's coldest temp and turn A/C off. You shouldn't experience this on/off if you were in really hot weather with fan on high.

If it didn't regulate like that then the condensation from the condensor would freeze and eventually block the condensor and airflow.

Just seems that ford has an awefully loud compressor clutch on our Mustangs.

If you hear the clutch cycling on and off and all your getting is warm air, you have a problem. (Low R134 Charge, plugged orofice, etc...) Get it to the dealer.