2001 A6 2.7t bad noise on cold startup
 

Hey what's up everyone first post here!
I wanted to ask this question to see if anyone else had ever had this problem- when I start my car cold there is a very high pitched screeching/grinding noise coming from the front of the car. It sounds to me like a metal fan catching just slightly on a housing or other object, but it does not sound good. It only lasts for 15-20 seconds then it sounds like something powering down and th noise stops. No affect on the noise by turning the wheel or revving which leads me to think it's a fan related with startup. Also no difference in power or performance drove up to ride last weekend and it handled the roads fine. I'm going in for a service/diagnostic soon but it's hard to describe this noise to my mechanic- anyone ever expericed or heard of this? Any advice is greatly appreciated.
Thanks!

Re: 2001 A6 2.7t bad noise on cold startup
 

Sounds like power steering pump.
Guess the oil is too thick when you fire your car up.
After a few second the oil flows thru the system and the noise is gone.

Re: 2001 A6 2.7t bad noise on cold startup
 

I am going to say it is most likely the Secondary Air Pump, part of the emissions systems. Commonly fail and make horrible noises. Since the sound does not alter while turning the wheel, I will almost rule out the PS pump, they tend to make a whirring noise, not a screech.

Re: 2001 A6 2.7t bad noise on cold startup
 

Im new to audi's but i have been a mechanic for a while, if its not either of the two above mentioned i have seen similar problems with the starter not disengaging after the car starts cold.

The grease in there can get thick to the point where it wont let the bendix gear kick out from the flywheel and it will hit something like 15k rpm causing it to whine until the gear retracts.

Re: 2001 A6 2.7t bad noise on cold startup
 

Classic SAI issue. Deleting that POS was one of the best things I did for my car! They usually fail because the rivets become loose and the turbine contacts the housing. They can often be repaired by removing the rivets and using bolts to hold the housing together. You can also remove it, but you'll need a block-off plate for the port into the cylinder head, and a resistor (10W, 330Ω) or ECU tune that can write out the code for it. It's a cold-start, emissions-only system, and won't affect how your car runs (really, it will be 'improved' since you're removing a failure point).

Re: 2001 A6 2.7t bad noise on cold startup
 

Agreed sounds like SAI Pump but I thought it would run longer than 15 or 20 seconds on cold startup.

Re: 2001 A6 2.7t bad noise on cold startup
 

Super thread resurrection here... but does anyone have any direction on HOW to replace the rivets with bolts or even disable the pump as mentioned?

Re: 2001 A6 2.7t bad noise on cold startup
 

I am sure it is the secondary air pump, had to do mine.

check this out to replace
https://www.audiforum.ca/a6-s6-rs6-7...install-72376/