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Discussion Starter #1
Hello,

I have an issue with my Saab engine from a few weeks. After the several hours starting the cold engine there is a strange noise which I think might be the timing chain issue. However I cannot find any video which will suggest me if I'm right. What is exactly happening?
You will find it in the video:

The car is Saab 9-3 SS, MY08 with the 2.0t (with stg1 - 210HP). Strange noise from the engine occurs when engine is cold and when I change gearbox to Drive position (you'll hear it around 20 sec on movie). When going back to P or waiting approximately 2 minutes, the noise disappear.

Can you confirm that this sound is coming from the timing chain? Or it might be something else?
 

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Sounds like a vacuum leak.
 

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Discussion Starter #3
Sounds like a vacuum leak.
You mean that the sound starting from the 22 second, might be the vaccum leak? For me it rather sounds like some kind of vibration or rattling.

In regard to vaccum leak, there are no issues with the RPM on idle.
 

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ahh, it sounds like rpm surges there at 22s. So you're saying tach doesn't move at all when that happens?
 

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Discussion Starter #5
In my opinion RPM are exactly the same. I even recorded one more video few minutes ago. After not driving the car for a few days I started it and when idle I think everything runs smooth.

On the video below:
0:00 to 0:08 runs smooth on idle (P)
0:08 to 0:24 you can hear rattling/vibrating on Drive (D)
0:24 to 0:37 again runs smooth on idle (P)
 

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I had a similar sound on my '08 9-3. Thought it was the AC compressor (replaced the bearing) but it was the serpentine belt tensioner pulley. It only made noise upon cold startup when the transmission was put into D or R. In P or N it was quiet and the sound didn't happen once the engine was warm.

In my case, the pulley bearing was worn and when the car was in D (or R) when on warmup idle the tensioner assembly vibrated causing the rattle. Once the bearing warmed-up and the idle was at ~900 it was silent (or made much less noise that wasn't discernable with the other engine sounds). I replaced the entire tensioner but would have gotten the same result by switching out the pulley alone.

Make another video with the hood open and the camera near the passenger/right side and have a helper engage and disengage the AC (using the AC Off button) with the transmission in P and then in D. It may only make noise when the AC compressor is running which caused me to think it was the AC. (Keep in mind that unless the AC Off button is illuminated the compressor is designed to operate nearly full-time - it's a feature of Auto climate control.)

If it is the pulley (or tensioner) the job can be done in about one hour. You will have to remove the air cleaner and the right side engine mount, jack up the engine slightly, and move the alternator slightly to provide enough room to get the tensioner out.
 

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Discussion Starter #7 (Edited)
@steve12955
I tried to record the video with engaging and disengaging the AC. What I've noticed is pretty interesting. First AC engagements noticeably increased the rattling effect, it was extremely noise and every next run was smoother. When the transmission put on P the effect of AC was neutral I didn't even notice any sound inside and probably you won't hear anything it on the video (at least I can't). I suspect you might be right with serpentine belt tensioner pulley.
Below you'll find a new video and some description what is happening. As I didn't have any person to help I tried to manage it by myself :)

0:00-0:10 N/A :)
0:10-0:21 running idle (P)
0:21-0:28 transmission put on Drive (D)
0:28-0:32 AC engaged 1st time
0:32-0:40 transmission put on Drive (D)
0:40-0:44 AC engaged 2nd time
0:44-0:46 transmission put on Drive (D)
0:46-1:16 transmission put on Park (P) with several AC engagements, which have almost no impact on the engine sound
1:16-1:22 transmission put on Reverse (R)
1:22-1:43 transmission put on Drive (D) with AC engaged with no noticeable sound effect

 

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AC sounds normal to me: when the AC is turned on for the first time after being off for some time, the compressor clutch will make a little more noise when it engages since it is initially pressurizing the system and the sound from the clutch engaging subsequent times may be less - at least that's how it is on my three Saabs.

The rattle sounds like mine did on my '08 9-3 2.0T. The rattle only appeared when in D or R when in fast idle and went away as the bearing warmed up and the idle speed was reduced - so it usually only lasted a minute or less. The only reason I noticed it is my cars are garaged and my windows were open one day as I was backing out. Had it been outside, or my windows been closed I might not have even heard it. However, the bearing was definitely shot.

Coincidentally, I have an '09 9-3 SportCombi 2.0T and the AC has started to whine when engaged. I had hoped it was the belt tensioner pulley so I replaced it last week, but it didn't solve the whine so I'll be changing the AC clutch pulley bearing soon.

If you decide to change the tensioner pulley there are a few other steps I didn't mention above. In addition, you have to:

  • remove the right front wheel
  • remove/pull back the inner fender liner (2 plastic nuts - heat them or they will snap off because of rust, 5 small bolts)
  • relieve tension on the belt by using a bottle jack under the pulley and remove belt...

Then from above, do the other steps I mentioned.




.
 

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Discussion Starter #10
I've repaired it!

Many thanks for suggestion @steve12955, in fact it was a serpentine belt tensioner. I've replaced it and everything runs smooth now.

Maybe this thread will help someone in future.
 

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I've repaired it!

Many thanks for suggestion @steve12955, in fact it was a serpentine belt tensioner. I've replaced it and everything runs smooth now.

Maybe this thread will help someone in future.
Glad it's fixed. I replaced the AC compressor pulley bearing on my SC yesterday and it took care of the whine.
 
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