So, recently, my '06 Mini has started making a noise. Noticed it at freeway speed - at about 60, sounds like a intermittent hissing (sounds like air purging) that comes and goes about every second ant, at 30, about every two seconds. Does it while rolling, clutch in or out. Every once in a while, on smooth or any surface, when applying brakes, I can feel the antilock kick in. I disconnected the battery for an hour and reconnected it and the noise stopped for about 25 miles then started again. Any ideas??

 

Really...nobody has an idea??

 

Sounds like a vacuum leak.
But I’m not sure if there are any vacuum hoses under the dash???
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Is the sound coming from under the dash/hood, etc?

ab

 

Around left front wheel area

 

Sounds like a boost leak...
Look at the intercooler boots....they do get stiff as they age.
trying to trouble shoot a sound on the internet is kinda like doing brain surgey from a diy box on yourself.....next to impossible. You just have to get under the car and look, wiggle and grab...be a detective!!

 

I guess I can add that, the noise does not speed up or slow down with engine speed. It is totally moving speed that affects the noise. I'm wondering if it could be a CV or something like that??