I have a 2001 180 Quattro, just did the rear cam tensioner seal n' a new valve cover gasket to go with it.

I was wiping some grime off the valve cover when I noticed the engine code stamped on the passenger side of the mill: ATC.

At first, that made me a little excited - I got
the thicker rod bolts n' slightly bigger OE downpipe, but then I thought "snap, the FAQ said those had the 'smaller ECU's that typically had to have new-tune software installed via actually soldering a new chip" (I also recalled that AWP's, not ATC's had VVT, but then if I don't have emission start-up VVT, what's that whistling or whoosh sound I hear from a dead cold start until the car warms up after a minute or two of idle?)

So does having the ATC motor mean I can't just get a OBD2 flash-software like GIAC-X?

Also, 'the hell is the start up sound if not VVT? Think of like a fan sound, but definitely not the radiator fans (I know what those sound like).

Thank you, guys

The start up woosh/whine is your secondary air injection (SAI) pump. Part of the emission control system. Those have a tendency to fail, in that the rivets that hold the two halves together fail. Very expensive replacement thru the dealer as there is no official repair....HOWEVER, for about $2.50 in nuts and bolts, you can repair it your self.

http://wiki.quattroworld.com/index.p...I_pump_rebuild

Cant speak to the flash versus solder for chipping. Recommend you contact the vendors directly and ask if they can flash your ECU.

cheers.

Okay, is it an expensive fail because if you wait too long to replace the bolts yourself, they'll snap n' fall into the system, knackering it?

Is the audible noise an indication of it failing already, or is it normally audible when working fine? I'm at between 78,000 to 79,000, should I be replacing those bolts about now? It looks like a right tight n' hard job .

Accesable only from the bottom (what side? The Wiki said it's by te power steering pump, but I just got the damn thing n' still don't know everything about the "starship Enterprise".)

The noise is probably the "normal" sound, so don't worry. As the revits begin to fail, the noise gets louder and more turbine like. If it fails, or if you have a related hose failure, your check engine light will come on...no catestrophic damage, no knackering. Worry not.

On the 225, it is lower left (passenger side) near the front. You have to pull the bottom plastic pan to see or access it. If you knew what to look for, you just might be able to see it from the top, but the engine bay is quite crowded and dark.

Cheers.