After not driving the car for about 10 days, I fired her up to run some errands. After my 3rd stop and drivng for about 30 minutes, I was able to hear what sounded like something boiling -- just forward of the cabin. It was most apparent when stopped at a light or in a parking lot. I could actually feel it with my foot when I had the brake pedal pressed. The car completely stopped making the noise within 5 seconds of shutting off the car.

The outside temp was 33 degrees and my temp guages inside the car all look normal.

What do you guys think this is?

 

Coolant running through various channels as the thermostat opens and closes, possibly? My car does that on cold days. Then again, I don't have a Porsche.

 

I tested the car again today and noticed that I only hear that sound when the brake pedal is pressed.

Any ideas?