Macster

Another goofy problem with my 2003 Turbo...

For a while now -- a month? -- I've been hearing some kind of rattle (not the best word but the best one I can think of) from the dash.

What I found is if I shut off the cabin vent fan by using the fan speed control button the noise stops when the fan is off.

Sometimes it remains gone when I turn the vent fan back on.

Other times the noise returns.

Nothing is blowing out the vents. The noise is irregular enough I do think the fan is the source of the noise, say from the fan blades hitting something. The fan is quiet at all speeds although at higher speeds of course the air rushing out of the vents generates some noise.

I think some air flow flap in the AC/heater system is somehow accounting for the noise. Maybe moving about almost like it is having a hard time holding or retaining its position.

AFAIK the heater/AC system works just fine. It has been cold enough here I have not had to use the A/C system much, but I use it once every few days for a while just to give it some exercise. When I do use it, it works without any drama. I have been using the heater more, but not with the A/C compressor active.

I turn off the fan using the speed control button, then adjust the temp control up to 72F. As soon as I begin adjusting the temp upwards the fan starts and once the temp is set to 72F I let the auto control take over and it adjusts the amount of heat and air flow and from where so that the cabin temp gets comfortable in practically no time and remains comfortable.

In this "mode" I do not hear the noise. It is when I manually adjust the fan speed and then adjust the temp control down to max cool say if I head out in the heat of the day for lunch. Then I hear the noise. Oh, the noise is not loud. I do not hear it over the AM radio. The only time is when the car is stationary and the engine is idling and the car is otherwise pretty quiet, as quiet as it can be with the engine idling. Thinking out loud maybe I'll try to capture a video/audio of the noise sometime.

Next time I'm at the dealer I will ask a tech about this noise and fill him in on the details and listen to what he has to say.

Hope the A/C system is not on its way out.

Atrox

Man I swear you are one of the most knowledgeable guys on here and it seems you have the worst luck. I hope it is something goofy like a piece of ac foam or an old air freshener. Hang in there.

up4speed

It sounds to me like there is either a piece of deteriorated foam, or a leaf or other object caught in the ventilation system or the blower. I had a flutter noise in one of my other cars, and it wound up being a leaf that got past the filter and caught in the blower motor.
The only part that confuses me is that you mentioned that it is not only related to the fan speed, but also the mode that you are in with the climate control.
If it was only fan speed related, I would be almost 100% sure that it is some debris in the fan, but since it's also related to mode, I'm confused.

jumper5836

Hopefully just debris, though the servo motors go bad in the newer models quite often, (cayennes, 997s, caymans) but I am not sure they are the same type that are in the 996.

jumper5836

Ya he's got a lemon.

"02996ttx50

macster, i believe we share the same " "rattle" for lack of a better descriptive. i have also not been able to isolate the source of it and continue to adjust the passenger side vents as it appears to emanate from there or the area near/around the dash speaker enclosure and first suspected the speaker enclosures screws. of course nothing could possibly be THAT easy!?. it;s annoying but not something i am going to spend money on chasing down, as every porsche i have ever had (5) has rattled to one degree or another. this only occurs when i'm twisting and turning, along with my headliner support wire which clicks like an imprisoned cricket lol. hate them both ( the rattles lol )

gl finding yours.. and yes, you DO seem to be experiencing a rash of niggling issues of late. good luck with them all. we would hate to lose you to a dodge challenger forum LOL