Hey Everyone,

I’m new to the forum, but been a reader for a long time (first time caller, long time lister…). I’ve owned my car more than 2 years with no problems (which seems to be mighty lucky considering what I’ve read of other B5’s), but alas, here I am with my own topic on the forum:

Car: 1998 A4 Avant Quattro 2.8, 5spd, ~95k miles, EVO Motorsports intake, GIAC chip, Miltek SS exhaust, Diesel Geek short-shifter, and some other mods that shouldn’t affect the car mechanically…

Symptoms: Commuted home the 26+ miles to my house in about 30 degree weather and just as I arrive the engine starts to sound horrible (mechanical description-fan hitting something, dumb@ss description-rocks in a blender). Either it just started or perhaps I couldn’t hear it over the stereo or road noise, though I would just about swear it just started as I pulled in the driveway. I back in, leave it running, and despite it being cold, dark, and rainy, I check to see if anything is stuck in the belt or fans, etc. Nothing. The next morning (also cold, dark, and rainy), I check again and find nothing and drive into work with a friend in case it’s something BAD. I have started it here and there over the past week or so (hoping to get a really good Christmas present), but the noise just gets worse. Revving the engine and/or driving does not seem to affect the noise other than increasing in speed with the rpm’s and other than the noise, the car seems to operate completely fine (though again, I have not driven it since it happened).

Clues: None of the accessory pulleys wiggle, nor the tensioner. The accessory belt seems fine. I stopped the belt-driven fan with a glove and the noise continued (BTW, the smaller auxiliary fan does not come on, though I’m in the D.C. area in the winter, so it probably shouldn’t). The engine cover, wires, etc. are all out of the way of the belt and/or fan. I have done all regular maintenance on the car over the past two years of owning it, though I HAVE NOT yet gotten around to replacing the timing belt. The cooling system DOES leak very slightly (I check it about once every two months and add about half a pint), though there is no apparent leaking from the water pump.

I will say I have my own theories, but prefer to get your unbiased ideas without me guessing at the problem. Any help you guys can give is GREATLY appreciated. Thanks!

 

2 areas to check, water pump because you have a slight leak somewhere next timing belt area "all pulleys/guides for worn bearings

 

The easy way to rule out all accesorys is to run the vehicle with the serp belt off. If noise disapears then you have a problem with one off your accesorys. If it remains there is a problem with either the engine or something drivin by the timing belt ( water pump, roller, tensioner)

 

i dont think is none of that cuz it has to do with wheel rpm ...i had a similar noise on my car....replaced the front wheel bearing both sides! it's good now...but wheel bearing wont make noise at low speed....maybe the vc or ball joints???? dont know!!