I've recently noticed this squealing on cold start but it goes away in about a minute once the car is warmed. I walked around the car and it appears to be the loudest coming from the passenger vent. You can really hear it at the 20 second mark. Any idea what it could be? The most recent work done was an oil change and serpentine belt in April. It's a '06 CS with 105K Kms. Thanks!

Link to dropbox wma audio file:

https://dl.dropboxusercontent.com/u/...tling_cold.wma

 

Can't play the clip.

My WAG is it is coming from the secondary air injection pump or the secondary air injection system.

This runs upon a cold start and runs sometimes about a minute depending upon ambient temperature.

If the noise appeared immediately after or shortly after you had the work done on the car, it could be a coincidence that this noise appeared after the car was worked on, but something could have been damaged, like an air line and the noise you hear is an air leak, and not the pump proper.

IF the noise waited until now to appear less likely it is due to something that was done during the service. Could just be a failing pump or a cracked/split line.

With the noise being so easy to reproduce the cause should be easy for a knowledge/qualified Porsche tech to id the source of the noise and fix it.

 

I don't know what it is, but it sounds metallic to me. What comes to mind is the belt tensioner pulley bearing, or possibly a pump or alternator bearing. It could be damaged and low on grease and it takes some time and heat to distribute whatever grease is left around the bearing, so it squeals till then. Just a theory.

I had a similar type situation with my old F430. The noise was more of a chirping, but it also went away after the car was driven a short distance. I thought it was the tensioner pulley, but the dealer told me it was belt related (there was a factory fix for it, but installing the kit was involved so I never had it done). Since you recently had the belt changed, it doubt it's that slipping.

Hope you get it fixed.

 

Thanks for the replies. I think the best way to describe it would be a whistling kind of sound.

 

There is a TSB for changing the piece on the oil pressure spring that can cause a squeel at 2k RPM on startup. $20 part or so.

 

If it is the oil pressure spring, do you think there's any harm for me to continue driving it, I figure since it does go away after about a minute should be ok? But I will look into the TSB. Thanks.

 

I cannot hear the clip, but your symptoms sound to me like the air/oil separator. I replaced mine recently after a squeaking sound that first led me to suspect a faulty belt or even a clutch release bearing. An easy way to check if it the AOS, is to remove the oil filler cap while the car is idling (the engine may sputter a bit and the revs will start to rise, so you should probably put it back before it goes too high, (I've never left mine off long enough to see how high it goes) , but the sound should go away immediately . The engine will return to normal as soon as you put the cap back. So if the sound goes away when you open the cap its probably the AOS, if not then its something else.

 

Sounds like your SAI pump needs to have it's bearing regreased. This is fairly common. The pump can be turned on with a Durametric or Porsche diagnostic tool to hear it better without starting the engine to confirm the source of the noise. New Pump is $400+ so find someone willing to take yours apart & fix it.

 

If there is any chance the engine is operating on less than ideal oil pressure, cold or hot, then no, I would not risk running the engine any at all. I do not like to tempt fate with any issues possibly related to oil supply or oil pressure, so I would recommend you get the car to a qualified shop and get the source of the noise diagnosed and fixed. Pronto.

If the noise is from the AOS I would again get the car to a qualified shop and get the AOS diagnosis confirmed and the AOS replaced.

Even if the noise was from a secondary air injection pump I would not continue to drive the car, but (you are getting ahead of me) instead get the car to a qualified shop for diagnosis and repair.

No noisy engine or failing AOS or noisy secondary air injection pump ever got better on its own with more use.

 

Will do, I'll try to rule out the SAI pump first and go from there. Thanks for all the help everyone, appreciate it!

 

Sorry for the dumb question. If it is the SAI pump, does it turn on initially during car warm up and then turns off is that why the whistling sound goes away? The reason I'm asking, if I drive over to a shop the car will be warm and won't have that sound.

 

Yes, the SAI pump runs at cold engine start.

If the distance to the shop is enough the engine gets warm then upon an immediate restart the SAI pump may not trigger.

The tech can let the car sit overnight and start the cold engine the next day.

Or the tech can use the Porsche diagnostics computer to trigger the SAI even if the engine is too warm. In fact I think he can trigger the pump even if the engine is not running.

You will have to ask.

 

So normally the SAI engages when the car is cold and then shuts off when the car is warm? So even if the car is warm and he can trigger the pump then technically he can still hear the noise if that's where it's coming from.

 

Might be a good time to buy Durametric

 

Well, technically the SAI is turned on when the converters are cold and turned off when they are warmed up.

I have more than once started my Boxster's engine and then driven car a few blocks far enough the SAI shut off then parked the car and shut off the engine for a minute or two -- to run into the convenience store -- only to come back and when I started the engine to have to SAI come on again.

But whether the car is cold or the converters are cold is just nitpicking (on my part).

Ideally the best thing is for you to be able to demo the noise to the tech.

The 2nd best thing is to tell him what it takes for the noise to appear. If this means leaving the car parked outside overnight -- so the tech has to start the engine like you start the engine -- so be it.

The goal is to demo the noise for the tech's benefit.

If the tech has to hook up the computer this can cost you extra. (He may have to anyhow, though.) And if the noise is not present when the SAI is run under artificial conditions -- it may require the SAI be trigged only when the engine is cold -- that can complicate things.

Ask the tech what he recommends, or prefers, but be clear under what conditions you have heard the noise. This SAI, if that is what it is, can't be his first SAI.