mmeggs

2004 A4 Quattro 1.8t B6

A couple weeks ago my daughter reported a "funny noise" coming from the engine.

I drove the car, noticed nothing at first, and then a a whistling noise kind of faded in for about 5-10 seconds and then faded back out. The car was moving, I came to a stoplight, sat at idle, and then heard it again.

It does not seem to be RPM dependent, acceleration dependent, or generally affected by anything the driver does. It just comes and goes, it quite loud, but otherwise does not seem to affect performance at all.

I have searched the forums but have not seen "whistling noise" described like this.

Thoughts or ideas about where to go with this?

kaseysdad14

You have a leak in your secondary air injection system. There's a hose that runs from a pump in the passenger side of the engine bay to the combi valve located in the back of the cylinder head. It's a plastic hose that becomes fragile with time. The purpose of the system is to help get the catalytic converter up to temperature and working sooner. It only runs when the car stops and only for the first 10 minutes of operation. It's not something to be excessively concerned with, I've deactivated the system on my 01 awm.

mmeggs

Well, the noise disappeared, for now at least.

All of these plastic components (hoses and valves) are cracking, one after another. It is maddening to get one fixed then another one fails. From what I've seen, no one sells a kit that allows you to replace all of them at once. This car has been a massive POS since about 85,000 miles. (Currently at 102k) There is *always* something wrong with it.

kaseysdad14

https://www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Engine/Emissions/ES2598096/
This is a complete hose system for the AWM engine. If you want to seriously cut down on the hose issue 034 Motorsports has a silicone hose kit that takes heat much better.

The cars are very well engineered. The problem is when a previous owner doesn't care and take care of it. The cars are not meant to work on Dino oil and Prestone. When the cars are given what they are supposed to get when they are supposed to get it they reward you in a wonderful way. If you were after a vehicle that would take whatever garbage was thrown at it, get an American car.