Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical Chat

Post Reply
 
LinkBack Thread Tools Display Modes
Old 12-11-2006, 10:49 PM   #1
Registered User
 
Join Date: Sep 2006
Location: Los Angeles
Posts: 373
New weird air/liquid leak sound from the engine

Was driving home the long way along an uncompleted freeway, driving mildly spiritedly. I pull into my neighborhood and my CD ends, and I notice a weird sound for the first time. I close my windows (top up), rev the engine a little and realize it's something new, it's coming from the engine compartment, and it's definitely throttle dependent.

It's like a PSSSHHHHT that sustains when the engine is under load. And if I blip it it'll PSHT! sharply, and sometimes again when it returns to idle. It's not the normal little suction sound you get from the outside, because the sound remains when the engine is spinning at 2 or 3k, and mostly because I can hear it from inside the car. I got no CEL, no oil warning, and examining the car afterward I'm not leaking anything. It's not really affecting performance as far as I can tell, although since I've heard the sound I'm in no hurry to really punch it. It sounds like a pipe is spewing something, or an air leak. I'm going to remove the compartment cover tomorrow and check it out before I drive it another foot.

Anyone encountered something like this? Is there a hose or pipe in the intake that commonly springs free or starts to leak?

-David

__________________
1995 Silverado V8 - Green/Tan (FOR SALE)
2000 Boxster S - Ocean Blue/Graphite Grey
2002 GSXR750 - Blue/White
http://www.darkoven.com/sig.jpg
David N. is offline   Reply With Quote
Old 12-12-2006, 06:39 AM   #2
Registered User
 
Join Date: Jul 2006
Location: Where the Sewer Meets the Sea, CA. USA
Posts: 2,695
Send a message via MSN to CJ_Boxster
Could be a few things like, bad oil separator, leak in your secondary air injection system, bad air injection valve, Bad electric vaccum pump. Im still hunting down my issue but im living with it for now... I have to buy presents and hold off on the car repair.

With me, it comes and it goes, its never an all day thing and its never an every day thing. I do notice when i hear this Psst noise that its more challenging to change gears smoothly without jerking the car back and forth during shifts.
__________________
--Proud Boxster Owner/Tech,

Carlos J Cazares

FastForward Performance
http://i10.photobucket.com/albums/a1...er/newsig1.jpg
CJ_Boxster is offline   Reply With Quote
Old 12-12-2006, 01:52 PM   #3
Registered User
 
Join Date: Sep 2006
Location: Los Angeles
Posts: 373
Thanks for the reply CJ, I feel a bit less worried now.

I took off the engine compartment lid, revved it a bit. Looks like it is definitely an air leak, sounds like it's coming from inside the intake manifold, perhaps around the resonance flap. It's a rushing of air that definitely increases with throttle. It echos around the manifold so I can't really isolate it any more than that.

The guy that was helping me saw the bracketed seals around the manifold center pipes were loose so we tightened those, but didn't affect the air rushing sound. I have no idea how to get any more specific about where the leak is coming from.

Anyone want to venture guesses? Is the resonance flap seal known to go bad? Is that pretty much the only valve in the intake manifold that would be a possibility?

-David
__________________
1995 Silverado V8 - Green/Tan (FOR SALE)
2000 Boxster S - Ocean Blue/Graphite Grey
2002 GSXR750 - Blue/White
http://www.darkoven.com/sig.jpg

Last edited by David N.; 12-12-2006 at 03:32 PM.
David N. is offline   Reply With Quote
Old 04-22-2007, 03:22 PM   #4
Registered User
 
Join Date: Sep 2006
Location: Los Angeles
Posts: 373
Yeah, for some reason it went away a day later. I have no idea. I'm guessing the intake got nudged when we tightened the screws, and somehow sealed up again. Or maybe the resonance flap was just sticking for a bit. Maybe pop the top and try tighting the screws on the intake seals, that's all I can think of.

You may also want to check air/oil seperator tho, I hear this can have similar symptoms. Run a search to be sure.

-David
__________________
1995 Silverado V8 - Green/Tan (FOR SALE)
2000 Boxster S - Ocean Blue/Graphite Grey
2002 GSXR750 - Blue/White
http://www.darkoven.com/sig.jpg
David N. is offline   Reply With Quote
Old 04-22-2007, 07:51 PM   #5
Registered User
 
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
Quote:
Originally Posted by CJ_Boxster
Could be a few things ... Bad electric vaccum pump...
Hi,

Where's that? Never heard of it?...

Happy Motoring!... Jim'99
MNBoxster is offline   Reply With Quote
Old 04-22-2007, 09:39 PM   #6
Registered User
 
Join Date: Jul 2006
Location: Where the Sewer Meets the Sea, CA. USA
Posts: 2,695
Send a message via MSN to CJ_Boxster
Hey jim, I'm reffering to the vaccum pump. I take it by ur jerk like responce that the vaccum pump probably isn't run by electricity which is probably what u should have said in the first place....

oh by the way Jim, thanks for the heads up.
__________________
--Proud Boxster Owner/Tech,

Carlos J Cazares

FastForward Performance
http://i10.photobucket.com/albums/a1...er/newsig1.jpg
CJ_Boxster is offline   Reply With Quote
Old 04-23-2007, 11:15 AM   #7
Registered User
 
Join Date: Jul 2006
Location: Where the Sewer Meets the Sea, CA. USA
Posts: 2,695
Send a message via MSN to CJ_Boxster
Did you notice any change in the idle while the hose was whistling?

__________________
--Proud Boxster Owner/Tech,

Carlos J Cazares

FastForward Performance
http://i10.photobucket.com/albums/a1...er/newsig1.jpg
CJ_Boxster is offline   Reply With Quote
Post 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 01:45 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page