Strange grinding sound for 60 seconds at start.
 

Hi All,

I have a problem on my 1.8t Audi engine. The car is from 2006 and has around 112000km run. I have done the oil/filter changes 2 weeks ago. Also I have done the Timing Belt at 90k km.

About a month ago my car started having an issue on cold starts.

Symptoms:
1. It happens only after a 8h - 10h period when the car is cold.
2. On the first start there is a strange sound like the car is struggling to get the RPM up, never fails to start on the first key though.
3. After 1-2 seconds a high grinding sound can be heard. This sound goes on for a maximum 1-2 minutes, depending on how cold is outside. After which the engine goes silent.

* All following starts will not emit this sound. Also the car runs smooth and revs smooth as well.
* Audi Service told me they have no clue of why it does that. They checked my Secondary Air System.
* There is an error that the car displays: "Camshaft Positioning Error" though the guys at the Audi Service told me that is not a problem. Even though the error did show again after they cleared it.

Other Symptoms:
1. I have noticed a minor loss of power. On autoban my car lost about 20km/h from the top speed.

I have also attached the two sounds captured with my camera. Please help me if you have any idea of what's going on. I don't want to start poring in a ton of money for investigations yet.

1. First Noise
2. Second Noise