buzzing noise airco fan (?)

[porsche356]

Hi All,

When I turn on the ventilation/airco in my 2003 TT I sometimes hear a buzzing noice. It is not allways there, as soon as I turn it off, the sound is gone, when I turn on the blower (speed is not important) the buzzing noice starts again. I think that I have to clean the fan, but i have no idea where it is located? Could somebody point me in the right direction?

Thanks,

frank

[3ball]

Hi All,

When I turn on the ventilation/airco in my 2003 TT I sometimes hear a buzzing noice. It is not allways there, as soon as I turn it off, the sound is gone, when I turn on the blower (speed is not important) the buzzing noice starts again. I think that I have to clean the fan, but i have no idea where it is located? Could somebody point me in the right direction?

Thanks,

frank

I know it seems too obvious, but tried turning on the AC and opening the hood and looking?

I have a 2004 with the same buzzing; it appears to come from the driver's side. I never bothered to look closer, but I do believe the noise is louder than before my 40,000 mile service.

[RFM]

There are mostly 3 possibility's for buzzing noises on Cayenne

1 - the blower located under the trim passenger side ( right side )

2 - PCM disc drive faulty

3 - Electric hot water pump to let the heater work for a short time when the engine not running, ignition on.

located in the left front wheel well against the door hinges

[DDiggler69]

I had this same problem on my 05'S. The dealer could not figure it out, so they replaced the entire fan system behing the dash (this was a 3 day job). The noise has not come back since they did it. My guess is that a motor bearing went out because the sound was "metalic" versus the sould that a leaf would make if stuck in the fan.

[porsche356]

Thanks for the replies,

I think that the noice is coming from the fan, because if I turn the fan off the noice disappears.

A 3 day job to replace the fan? This sounds like a challenge! Could somebody help me to find the fan (diagram, link or procedure)?

Thanks a lot,

Frank

[Dennis C]

My 2004 Cayenne S has been to the dealer for repair on a similar issue 3 times. This week, they diagnosed the problem as the "coolant after-run pump". There is a TSB regarding noise from this pump and a repair procedure. Mine is scheduled to be repaired today, and I'm picking it up this afternoon. Hopefully this will do the trick!

Initial diagnosis on this problem was "blend-air door actuator". This didn't fix it. They then looked at the blower motor, and realized this wasn't it.

My symptoms were very similar to what you describe - sometimes I heard it, sometimes I didn't.

Good luck with yours... I'll let you know if this fix works on mine.

[porsche356]

Hi Dennis,

Thanks for the reply. Just checking: did the sound disappear at cayenne also when you turned off the fan?

We are talking (in your case) about engine coulant, not airconditioning fluid, right?

Thanks and good luck with your car.,

Frank.

[Dennis C]

Hi Dennis,

Thanks for the reply. Just checking: did the sound disappear at cayenne also when you turned off the fan?

We are talking (in your case) about engine coulant, not airconditioning fluid, right?

Thanks and good luck with your car.,

Frank.

Yes, the sound did (generally) disappear when the fan was turned off. It could also be heard very clearly when the engine was turned off, and the heater was activated. The noise was not consistent, although it only appeared when the engine was warm.

I believe this is engine coolant, as this is used for the cabin heating system.

[RFM]

Blower motor replacement time: 1 ( one ) hour !!!

Most difficult point: find a 5,5mm key.

Regards.

[porsche356]

Hi Guys,

The quest went on today. Found out that it has to do with the airco. When I put the climat control on écon'then the sound it gone. Noticed as well today that the sound is the loudest under the hood. Does this sound like the coolant after run pump that Dennis talked about? If not what could it be then?

[RFM]

When you put the air condition on ECON, you shut off the air con. compressor. It means that the air con. is off but all other functions stays working, trey with refilling the system in a workshop and do a search for a leak. If the buzzing is still there it could be a compressor issue.

The compressor is not the hot water pump that Dennis talked about.

[porsche356]

Hi,

Thanks for the quick response. Must say that I am completely puzzled. Just took the car óut''for a spin and now the sound came after 3 minutes of driving and did not, as said before, disappear when I turned the airco on econ. The sound only disaapears when I turn off the blower. This makes me think about the blower again. Strange thing is that the noice appears to come from under the hood and not the driver side.

Perhaps I can check some things tomorrow.

Thanks

[RFM]

Do you have a RHD or a LHD car? The blower is located under the trim passenger side ( right side for LHD cars ) under/behind the glove box extremely right. The trim and blower removal is easy.

[porsche356]

I have a LHD drive car

[mudman2]

RFM

5.5mm wrench or torx ?

Mike

I have a LHD drive car

[RFM]

5,5mm wrench, torx have not mm indication.

[porsche356]

Hi Tried to find more clues, but so far I came up with this:

- sound is a constant 'buzzing' noice

- sound appeard not directly when the car is started, but after a short period (2-10min).

- sound disappears when the airco is set to OFF

- sound does not change in loudness when the fan speed changes (fast/slow)

- sound seems to come from the engine area

- there is no difference in auto or econ mode

Any clues? Are there any turning parts that I can check?

Thanks,

Frank

[Dennis C]

Hi Tried to find more clues, but so far I came up with this:

- sound is a constant 'buzzing' noice

- sound appeard not directly when the car is started, but after a short period (2-10min).

- sound disappears when the airco is set to OFF

- sound does not change in loudness when the fan speed changes (fast/slow)

- sound seems to come from the engine area

- there is no difference in auto or econ mode

Any clues? Are there any turning parts that I can check?

Thanks,

Frank

See TSB #1945.

[porsche356]

Dennis,

Feel a bit stupid, but what do you mean by TSB #1945? Tried the search but nu result.

Thanks, Frank

[Loren]

He is referring to Porsche Technical Service Bulletin (TSB):

1/04 1945 Operating Noises of The Additional Coolant Pump -- dated May 25, 2004

Porsche TSBs are available here to view online by our Contributing Members.

[porsche356]

Hi Loren,

Thanks, I was not aware.

Frank

[porsche356]

Hi,

Just looked at TSB1945 and I was wondering whether I can do it with 'ordinay' foam insulation tape as well. Or do I need the special porsche tape? (prefer to buy some heat resistant foam tape at the DIY than going to the dealer on saturdays).

Thanks,

Frank.

[porsche356]

Hi,

Finally had the TSB1945 done at the workshop. Unfortunately the sound is still there. I did some more investigation:

- sound comes from the left (driver) side from the cayenne turbo.

- sound is best heard under the engine lid, left towards the dashboard (where the brake fluid (?) is)

- sound only appears when the engine is warm

- airco on off does not make a difference

- when the fan is off the sound is gone

- fan on and the sound is there

- when the temperature is set low the the sound is gone

- when the temp is set to warm the sound is back.

Sound is best described as a continuous humming sound. What is turned on permenantly (linked to the fan) and could make this noice (not the fan!!)??

Any ideas, I am slightly puzzled on this one.

(Air suction?)

[RFM]

See previous post: RFM jan. 22 point 3

Dennis C jan. 25 and 30

Loren jan 31

[porsche356]

Hi RFM,

Thanks again for the quick reply.

Regarding the after coolant pump (TSB 1945). This has been done (correctly I hope) and the sound is still there.

I thought of the warm water pump as well. But could this make noice as well when the engine is running?

Thanks, frank