'06 MCS with DDM Works CAI and Stratmosphere catback.

At approx 56,000km on the odo I began to hear a sound that can best be described as a mechanical actuator flap/butterfly opening/closing at 21km/h. No whirring or squeaking. More like a spring sound that lasts for approx 1/10th of a second.

Always at 21 km/h and always and only after the car has been started.

The sound is coming from the engine bay.

The sound only happens after the car has been started and first driven over 21 km/h. Once the sound has happened it never recurs until the engine is stopped, restarted and the car driven to 21 km/h. In other words, once it happens, I can drive normally and I'll never hear it again. I can stop at stop signs and then accelerate away and the sound does not recur at all. Only when I stop the car, turn off the engine, then start the engine and start driving again will the sound recur - and always at 21km/h.

It sounds like a flap or butterfly valve being opened or closed by an actuator and it always and only happens at 21 km/h and only after the engine has first been started.

Bizarre - and you know what? I hate the fact that I'm sensitive to all the sounds coming from my Mini. Makes ownership a bit of a downer. sigh.

Any ideas?

 

Is that the speed that the auto-lock function occurs at? No idea what else activates at a certain speed.

 

As far as I know, around that speed, ABS unit tests itself and it makes that kind of sound.

 

Auto-lock was disabled when I took delivery of the car - mindless feature imo.

ABS unit - hmmmmm......just dropped the car off at the local dealership this morning. Will have them check into that.

Thanks for the suggestions!

 

Check this one.

http://www.mini2.com/forum/faq.php?f...q_clunk_faults

This might be the one you are looking for.
12mph = 20km/h