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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHSaw noise on start up
Reported or suspected cause
air pump
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0
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1
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0
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Suspected cause
If the secondary air pump comes back on and is noisy, probably the air pump.
Leading evidence: 'air pump' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'air pump' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check belt' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
As stated above - remove belt and run motor, if still there check the pump as decribed above
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When I start my car up there is a high pitched saw noise coming from around the area that the coolant tank is located. It seems like its coming from the cylinder right in front of the coolant tank, then it eventually goes away after the car is warm. Is this normal?
The belt seems to be fine, it really seems like the noise is coming from whatever is in front of the coolant reservoir, i have a 2001, the first picture here doesn't have thing that I am referring to, but it is that empty space.
http://www.renntech.org/forums/index...on-a-my99-996/
it goes away after the initial warm up when the RPMs go down.
A noise upon startup that goes away in a minute or so might be the secondary air injection pump. Generally these are rather quiet -- sounds like someone running a Hoover vac next door, but if the pump going bad or one of the air injection lines cracked the thing can make a racket.
Have the engine cover open, engine dead cold, with you standing outside of the car at the rear.
Locate the air pump as best you can. Follow the air lines from the pump to the engine and note their position.
Have someone start the engine and just let the engine idle. Try to pinpoint the noise. See if it is coming from the air pump or from around one of the air lines to the engine.
Keep your hands, clothes, hair away from the moving parts of the serpentine drive belt.
If you hear the noise have the helper shut the engine off. Restart. My experience is the secondary air pump will not come back on with this restart (your car might be different though) and if the engine quiet air pump is the likely culprit.
If the secondary air pump comes back on but is quiet then the noise something else.
If the secondary air pump comes back on and is noisy, probably the air pump.
Added: Also, as I'm sure someone noted you can remove the serpentine belt and start the engine and let it idle a minute or so, if engine dead cold. If the noise not present you can then begin searching for a cause from one of the accessory drives. Check all pulleys for any radial or axial play. There should be none. Check the belt for a sharp edge. If there's a sharp edge the belt's rubbing and its rubbing cause a drive has play and the pulley is out of position.
Sincerely,
Macster.
here is a link to a video i took of the sound, if you wait until the end, the high pitched saw sound goes away....
http://www.youtube.com/watch?v=0KaEMCm4FMQ
Well that video cancels my asking what type of saw. That's a high speed saw sound not a hand saw, jig saw, or saws all. Play with it since it wants attention. Try moving the mentioned air lines. I'd bet on the same secondary pump already mentioned but another side bet on oil filler cap since it might be suckings air past a seal making noise like that till it seals. What ever it is everybody knows you have it thats for sure. Man what a racket hehehe.
the question wasn't what type of saw noise was coming out of my engine, it was what was making that noise!!...it does sound like a table saw though...I used to think it was the construction guys working down the street, until I opened the hood.
Who heck drives around with a table saw in the back seat of their Porsche?
I stand by my secondary air injection pump theory but I never thought one would make that sound, if it proves to be the air pump.
One thing you can do, if you want to go to the trouble: If you can find and get to the wiring harness connector of the pump and disconnect it or find the fuse for the pump circuit and pull it and see if the noise still present.
I do not know of there is a fuse for this circuit. I seem to recall there is one but you'll need a fuse box diagram for your car to be sure.
Disconnecting the pump or removing the fuse may cause a check engine light event when you start the engine so be prepared for that.
Sincerely,
Macster.
darn, you are probably right. The car only does it on a cold start. I have a warranty on it, so probably don't want to go through the hassle of having my check engine light turn on. Maybe I'll just go to porsche and tell them that there is a saw under my hood.
Oh, yeah. If you have warranty on the car just take it to dealer and explain when symptom appears. The key to repairing these things is to be able to reproduce the symptoms reliably.
Be sure to post a follow up. Ask how the cause of the noise was diagnosed?
(Might get a shrug and something non-committal: An auto mechanic friend of mine years ago told me that after a while when he or his co-workers saw a particular model of car come in they almost always knew what was wrong. Experience from working on the same brand of cars over the years pays off.)
Sincerely,
Macster.
So whatever happened with this? I've got a similar, but quieter, noise. It does seem to be the air pump as the noise changes/goes away with the pump unplugged. Do I just replace the pump, or could it be a hose/vacuum fitting somewhere in the system causing this?
Shawn
Sorry, no pics but
My air pump was doing the same thing, nasty saw like squeal when cold. I took it apart and found it was
chock-a-block full of brake dust. I blew it all out with compressed air, cleaned it all up and oiled the bearings upon reassembly. It has been blessedly quiet on cold starts for over one year now.
Super easy fix. Maybe 60 minutes fooling around.
40A fuse (big sq one) for air pump is located behind rear seats on a relay board. You'll pop a CEL as Mac says if you start it up and run it with the fuse out so you'll have to find someone with Durametric software to clear it for you if you can't do this yourself.
Im not sure but I think it is sitting right there on top mounted to the body.. In front of the coolant res.. Well behind it.. But in front of it from where you are standing.
Thanks for the info!!!
My car occasionally makes this sound upon start-up, however it doesn't do it everytime. I knew the sound was coming from the air pump but I just assumed the bearings were worn and I was eventually going to replace the unit. I'll give your cleaning trick a try.
Okay, this thread makes a LOT more sense upon reading it... When I saw the subject my first thought was "Holy crap, how loud does a sound have to be before you can
see
it?!?"
Well I guess i can join the growing group which has this noise
Jeezzzz this thing isn't contagious is it
Not quite as bad as your's but will certainly try what's suggested, thanks for the thread and posts!
Did you take it into the dealer yet (I also have warranty, maybe I'm better of letting of letting them deal with).
All feedback appreciated!
Cheers,
Sid.
Yeah but the "diagnostics" are not and that usually adds up to 70% of the labour
Sometimes you're better (cheaper) of doing it yourself.
One way or another...they always get ya.
I have to find time to take the Secondary Air Injection (SAI) apart and see if I can clean it. The noise is certainly better than before. It was making a racquet at first...
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