» View Question

physed 12/5/2011

2009 Mini Cooper S 4 Cyl 1.6L


Engine makes sound of deflating balloon when shut off

I have a sound coming from the back (near Firewall) of the engine when I turn the car off, which sounds like air escaping from an untied balloon. Any ideas?

2 Answers

Spoon Sports

Spoon Sports 12/5/2011

make sure the vacuum hose on the fuel pressure regulator is on, on the bottom of the fuel pressure regulator on the fuel rail, its a small black vacuum line that hooks to the nipple of the regulator. OR it might be the refrigerant (A/C) pressurizing or something. My MCS does not do this, but my other vehicles do this after driving w/ the A/C on. The hotter the day, the longer it "hisses" for.

Try running w/o the A/C on (even better w/ the whole auto a/c system shut down), and see if your car hisses at you after a drive.


I might be the supercharger, i blieve the S has one equiped. Whether it's somehow depressurizing or coasting to a stop, you can hear it because the engine is off.

By the way, welcome to the club, you are not alone

Spoon Sports

physed 12/6/2011

Thanks for the help. I understand there may have been an issue with some of the fuel pumps on Minis, so I'll start with the vacuum hose on the FPR. I'll let you know what the outcome is.

Spoon Sports

Spoon Sports 12/13/2011

Sure thign chief.



Answer this question

( characters left)

Follow Question

what's this?