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

Reply
 
LinkBack Thread Tools Display Modes
Old 09-22-2012, 01:13 PM   #1
Registered User
 
tonycarreon's Avatar
 
Join Date: May 2009
Location: Frederick, MD
Posts: 1,396
odd idle + oil cap question

so a while back (this year) i replaced my AOS (no smoke or issues. just time+mileage).

prior to that i tried the "remove the oil cap" test, which went fine. no problem getting it off, just a very slight suction.

today i pulled out of the garage and decided to add a little oil (it was slightly low) and when i pulled the cap i noticed the car really didn't want to idle well. i don't remember that happening before replacing the AOS. once i put the cap back on it returned to normal idle.

so my question - when removing the oil cap, should the car idle poorly? if i remember correctly before AOS replacement, it used to idle faster until the cap was put back on and then returned to normal.
__________________
"Speed has never killed anyone, suddenly becoming stationary... that's what gets you."
tonycarreon is offline   Reply With Quote
Old 09-22-2012, 01:30 PM   #2
Registered User
 
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 5,102
Yes, the crankcase is running under a slight vacuum (via the AOS system) to aid ring sealing; taking off the oil cap creates a vacuum leak which can cause the car to run rough.
__________________
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
JFP in PA is offline   Reply With Quote
Old 09-22-2012, 01:51 PM   #3
Registered User
 
tonycarreon's Avatar
 
Join Date: May 2009
Location: Frederick, MD
Posts: 1,396
great. thanks JFP!
__________________
"Speed has never killed anyone, suddenly becoming stationary... that's what gets you."
tonycarreon 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 04:08 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