Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Reply
 
LinkBack Thread Tools Display Modes
Old 05-14-2013, 09:54 AM   #1
Kur
Registered User
 
Join Date: May 2013
Location: London
Posts: 6
Buzz/hiss coming from the fromt of a 986

Hi.
I am now to this forum and not quite techie, just a word of warning.
My Porsche 986 Boxster, 2.5, 1998 has developed a fault which so far doesn't look to be too major, but is quite annoying at least.
There is a noticeable noise coming from the front, it seems somewhere just behind the main console. It doesn't seem to be connected with the operation of the air conditioning, since it is there even if the AC is off.
It changes its frequency according to the revs of the engine - starts as a faint buzz and when revving the engine up or accelerating goes to high pitch whizzing. It doesn't depend on the speed but on the revs of the engine alone. Sometimes it is not there at all, sometimes it is quite noticeable.
Could it be something to do with the dynamo? Or could it be the clutch, which I have replaced recently? Or as far as I know there's some fan there, could it be faulty?
Any recommendations of how this could be fixed will be very welcome.
Thanks!

Kur is offline   Reply With Quote
Old 05-14-2013, 11:42 AM   #2
Registered User
 
Join Date: Sep 2008
Location: Florida
Posts: 2,087
I don't know what a dynamo is...
Clutch noise would be be behind you not in front.
Is your radio on? AM by any chance. buzzing that rises and falls with RPMs can be electrical noise coming through your radio antenna ground.
dghii is online now   Reply With Quote
Old 05-14-2013, 01:30 PM   #3
Registered User
 
Join Date: Apr 2012
Location: Ontario, Canada
Posts: 598
Good suggestion dghii. The dynamo would be the alternator and, as with the clutch, any noise would be coming from the rear and not the front of the car. Radio interference can easily increase and decrease in intensity with engine RPM's, unlike noise from the fans for the radiators or HVAC system, so that would be my best guess as well.
southernstar is offline   Reply With Quote
Old 05-14-2013, 05:21 PM   #4
Registered User
 
thom4782's Avatar
 
Join Date: Sep 2010
Location: Foster City CA
Posts: 1,085
My car makes a buzzing or whining like noise from the front when the AC is on. This happens even when the temperature is set so there is hot air coming out of the vents. Porsche runs the AC to dry the air being circulated in the car even when heating.

Try this to see if the noise is AC related. With the engine on and the AC snowflake showing on the LCD display, listen for the noise. If you hear it, push the snowflake button on center console so that it the snowflake disappears on the LCD display. If the noise goes away, then it's AC related. Most likely, it is coming from the expansion value of the evaporator. One is cheap to fix. The other is costly.
thom4782 is offline   Reply With Quote
Old 05-15-2013, 06:45 AM   #5
Registered User
 
dagdisco03's Avatar
 
Join Date: Jul 2012
Location: CT, USA
Posts: 104
Garage
Look inside your fuel door on the right fender. With it open look to the front side of the opening and you will see vent holes. There's some fuel vapor switch that fails inside the fender that you can fix and it will stop the sound. I put black duck tape over the holes and have put on 10K miles with no check engine light. Buzz/hiss sound gone. I'm 100% sure that's what you are hearing. If you search around with that in mind you will see some write ups with part numbers and prices and how to change it out. Wasn't worth the effort to me you will never know the duck tape is in there. : )
__________________
2000 Boxster S
dagdisco03 is offline   Reply With Quote
Old 05-15-2013, 07:00 AM   #6
Kur
Registered User
 
Join Date: May 2013
Location: London
Posts: 6
Thank you very much for your responses, folks. Much appreciated!
It is definitely not the radio (I'm not a complete idiot, I hope), neither the AC.
It could be this thing with the fuel door - I will check and report.
The thing is this sound follows exactly the revs of the engine. It must be some sort of belt or something which depends on that. I don't know... It wasn't there the last 3-4 times I used the car and yesterday it was back.
I hope my English doesn't make things more complicated.
Kur is offline   Reply With Quote
Old 05-15-2013, 07:31 AM   #7
Registered User
 
EssexPorsche's Avatar
 
Join Date: Feb 2013
Location: Essex, England
Posts: 276
Garage
Naaahhh , these cats love us English boys!
__________________
Don't care......was made to care! (my Mum)
EssexPorsche is offline   Reply With Quote
Old 05-15-2013, 08:12 AM   #8
Registered User
 
Join Date: Sep 2008
Location: Florida
Posts: 2,087
Wan't trying to imply you were an idiot...trying to troubleshoot sounds over the internet is pretty tough. Just trying to eliminate possibilities. Good luck.
dghii is online now   Reply With Quote
Old 05-15-2013, 08:46 AM   #9
Registered User
 
thom4782's Avatar
 
Join Date: Sep 2010
Location: Foster City CA
Posts: 1,085
If you are confident it isn't the AC, then I won't comment further other than to say this.

There are no belts up front that would make the sound coincide with engine speed. The reason I suggested AC is that the flow of refrigerant in the AC system is related to the speed of the AC compressor. And the AC compressor is driven by a belt back in the engine compartment. The AC noise I mentioned in my car changed with engine speed until I turned the compressor off using the snowflake button.
thom4782 is offline   Reply With Quote
Old 05-17-2013, 08:31 AM   #10
Registered User
 
dagdisco03's Avatar
 
Join Date: Jul 2012
Location: CT, USA
Posts: 104
Garage
Figured I'd find the rest of the detail for you since it seems to be less common of and issue then I thought. Part # 996 605 213 01 again tape over the hole is all it takes to stop the noise. Someone's picture of the hole I'm talking about at the fuel door. Item 9 in the parts list view. This is for the kazoo, howling, blowing into a bottle sound that changes with RPM, load and speed.
Attached Images
   
__________________
2000 Boxster S

Last edited by dagdisco03; 05-17-2013 at 08:31 AM. Reason: Double posted pictures
dagdisco03 is offline   Reply With Quote
Old 05-17-2013, 08:35 AM   #11
Registered User
 
dagdisco03's Avatar
 
Join Date: Jul 2012
Location: CT, USA
Posts: 104
Garage
To add to this the main console you are talking about is the dashboard or shift area not the armrest or behind the seats.
__________________
2000 Boxster S
dagdisco03 is offline   Reply With Quote
Old 10-22-2013, 08:21 AM   #12
Kur
Registered User
 
Join Date: May 2013
Location: London
Posts: 6
Thanks!

Hi. Sorry for getting back to the discussion with such a lenghty delay.
I attampted covering that hole, but tis didn't solve the problem.
dghii seems to be right by suggesting the the noise seems to be connected with the radio operation.
The thing is the noise is there only while the radio is OFF, as soon as I put it on, it goes away. Weird, innit?! I guess I need to have it checked... or just continue listening to my favourite tunes at all times.

Kur is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 09:29 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page