Has anybody heard a loud hissing sound from the engine bay when they turn their ac fan on? The car seemed to just start doing this and it is driving me crazy. Oh, and the car is a 99 c2 cab tip (would probably help to let you guys know). Did a search but nothing popped up. Thanks in advance.

 

i have a strange noice from the right rear on my 99c4. don't think it's from the a/c. only gets very loud/annoying when i leave my foot on the gas to maintain speed. when the foot is off the gas or when i accellerate it goes away.
i have replaced the tires, balance and aligned all four wheels and it didn't solve the problem. i 've schedule a visit to the dealer next week to have it check out. well let you know what it is next week.

 

Although I can't help, I can commiserate. I also have a 99 Cab, and my A/C intermittently makes a buzzing noise from the passenger side dash, close to the speaker. It usually only happens when it is very hot out, and it buzzes when I come to a stop. Once I give the car some throttle, it goes away, but then returns when I am not giving it any gas. I've had it in to the dealer twice - once they thought it was a fan motor out of alignment, but that solved nothing. The next time, they consulted with Porsche NA techs and said they fixed it, but it came right back. Very annoying, but hard to duplicate when I take it in. Any ideas on this one?

 

carcrazee, is the noise on the c4 that your describing almost like a light grinding sound? If so, my cab has a similar problem, although the sound appears as I let off the gas and disappears when I am on it. I usually notice this on the highway.