AOS breather hose keeps popping off
09-18-2012, 01:13 PM
#1
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AOS breather hose keeps popping off
Since we replaced the AOS (1) on the 2000 996 and replaced the rubber o-rings (12) on the breather hose (4) on both sides, the breather hose will pop loose, most prevalently from the AOS connector side.
This will happen after running sustained RPM's over 5,000. If you stay below there, even a few thousand miles will not "wiggle it" loose.
Could this be a pressure issue, a faulty AOS or just tired plastic squeeze connectors?
We also checked the correct position of the scavenger pumps, just to be sure.
This will happen after running sustained RPM's over 5,000. If you stay below there, even a few thousand miles will not "wiggle it" loose.
Could this be a pressure issue, a faulty AOS or just tired plastic squeeze connectors?
We also checked the correct position of the scavenger pumps, just to be sure.
09-18-2012, 02:56 PM
#2
Race Director
Since we replaced the AOS (1) on the 2000 996 and replaced the rubber o-rings (12) on the breather hose (4) on both sides, the breather hose will pop loose, most prevalently from the AOS connector side.
This will happen after running sustained RPM's over 5,000. If you stay below there, even a few thousand miles will not "wiggle it" loose.
Could this be a pressure issue, a faulty AOS or just tired plastic squeeze connectors?
We also checked the correct position of the scavenger pumps, just to be sure.
This will happen after running sustained RPM's over 5,000. If you stay below there, even a few thousand miles will not "wiggle it" loose.
Could this be a pressure issue, a faulty AOS or just tired plastic squeeze connectors?
We also checked the correct position of the scavenger pumps, just to be sure.
It occurs to me it might be (long odds but...) a faulty AOS though blowing hoses off connectors is not an AOS failure symptom I've ever come across.
Which brings me to: Simplest explanation is the best and usually the correct one: Tired plastic squeeze connectors. I mean they're plastic, they work by squeezing...
That they've come loose now means they were wiggling around for a while before they came loose and this could have degraded the connection integrity to the point they'll never be right.
Not sure how hard/costly this is but I'd seriously consider renewing these.
I'm not at the car but you are or someone is and maybe looking things over with an eye to determining the feasibility of an alternative method of clamping and securing these hoses is worth the time/effort.
Trouble is these are not I believe designed to accept some other off the shelf hose/tube clamp device but a good mechanic might spot some suitable work around.
So trying to adapt something could bring with it more problems than it solves.
Thus, renew these along with the hoses to which they are attached would be my advice.
Sincerely,
Macster.
09-18-2012, 04:41 PM
#3
Rennlist Member
Normally those hoses are very difficult to remove, so it sounds like the built in clamps are worn out & relying on engine vacum to keep them in place. Once engine vacum drops at high rpm they work loose. Unless the new O-rings are the wrong size preventing the clamps from locking in place. My 2000 model has the original hoses which have been taken on & off many times with no issues.
