Hey all,

I was wondering if anyone may have experienced this before, or know anything about it:

My 05 MCS JCW has recently developed a distinct hissing sound when turning on the A/C. This is what I have observed:

1. It hisses intermittently, so not every time I turn on the A/C.
2. When it does hiss, it only does it when first turning on the A/C when the engine is cold, or if the A/C hasn't been used for a couple of days. When I turn off the A/C, the hissing stops.
3. At first the hissing is constant, and then it becomes intermittent until it finally goes away after 5-10 minutes.
4. I can only hear the hissing sound from inside the car, and it seems to be coming from around the center stack on the drivers side.
5. It hisses regardless of the temperature setting, air flow directions, circ/recirculate, etc.
6. It is still blowing cold, even in 90+ degree weather we've been having recently.

So, based on my observations, any ideas of what it might be? Could it be doing any damage to the A/C unit?

My thoughts are that it might be the compressor, but I am not sure where it is located.

Any help anyone could provide would be mucho appreciated! Thanks!

 

 

Yup! That pretty much sums it up!

Interestingly, my Mini stopped hissing at me Yesterday morning, and I thought cool...it resolved itself. Well about a mile down the road, after a stop sign, the acceleration power just cut out, went right into limp mode and the Service Engine Soon light & EML light lit up nice and bright! Limp mode was scary enough with a big truck behind me...at least it didn't happen to me on the freeway!

I 'limped' my way to the dealership a couple miles away (lucky me!) & left it in the service bay.

Perhaps my car went from a resentful hiss to a downright temper tantrum...he's never been too fussy before!

 

So I got my Mini back from the dealership, and it turns out the throttle valve went bad. All fixed under warranty.

I asked my SA about the hissing sound and he said that it was normal, and that they all did this. He said that the piping for the A/C is very small and narrow, which was the cause of the hissing. Honestly, I never noticed it until I drove with the A/C on and the radio off...and I don't run the A/C often here in Northern CA.

I've never noticed my partner's Mini make this hissing sound before, but then again, he always has the stereo going too. Am I being overly paranoid?

 

Just an update to my hissing problem. In August, I hit a trash bag on the freeway at 65 mph, which damaged the front bumper, knocked in my passenger fog light, which was attached to the radiator mount, which was shattered in that area. A stick in the garbage bag also knocked a hole in the A/C condensor (thank goodness!).

The body shop noted that I had a slight inward curve (toward the radiator behind it) to the entire length of the A/C condensor , which is wierd because there was no way a bag of yardwaste could have damaged the condensor in that way (there was no damage to the aluminum crash bar behind the front bumper). Anyway, long story short, after replacing the condensor & evap unit, no more hissing! Yay!