Hi all.

991.1 4S (‘14) with 18k miles. As of a few weeks ago the exhaust note has changed to a deep humming sound instead of the deeper gurgling noise when PSE is on.

It sounds like nothing is changing between it being on and off but it is not even the old “off” sound. Almost an in between sound that increases to a hummmmmm noise.

Is there an actuator/butterfly that may have gone bad? Has someone experienced this? Something I can check before heading to the dealer’ service department? I’m under CPO.

I’m in South Florida so wondering if the 90% humidity and 100f weather may have affected something.

 

I'm central Florida, 90 90 plus here as well. No change in my PSE sound.

Your issue sounds like a mechanical fault, maybe the valve isn't fully opening or there's an obstruction. I have found critters in the strangest places, South Florida is full of them. I know, I lived there for 40 years.

Take it to the dealer, let them figure it out.

 

Might be the changeover/bypass valves. Lots of threads discussing the failure, and this may help: https://rennlist.com/forums/991/8002...-on-991-a.html

 

The PSE uses a vacuum-operated valve in each side of the exhaust. You can look under the middle of the rear bumper and see the actuators move the valve linkages when PSE is turned from on to off and back again.

 

Thanks guys. Seems likely the culprit/s. Will know more on Thursday at the dealership.

Best.