Hello - this is my first post here, and hopefully it's not as painful to read as it is to write. I have a 2002 A4 Avant 1.8t with 76k miles on it. This is my second Audi - my first being a 2000 version of the same car, which met an unfortunate end when I hit a deer three years ago... On my last one, I had replaced and/or upgraded the control arms, water pump, timing belt, clutch and other miscellaneous parts by 80-90k. That was when I had a reliable garage and more money to do more work at the same time. Not I am trying to be more frugal and taking on some of the work myself. Since most of the parts were replaced before there were issues, I never encountered any failures. But now I am getting worried because I am hearing new noises and feeling some new shudders as I drive. The most worrisome is the loud hum that is coming from my ? It sounds like its coming from teh engine, but I don't hear it in the engine compartment when outside the car. its almost like its a vibration that is echoing through the interior. this is coupled with lower mpg and a long warm up time, sometimes 2-3 times longer than usual. I just got new tires and that may account for a lower mpg, but it's gone from 27-28 average to around 23. That seems like a considerable drop. Does this mean I need a new water pump? Along with this I have a new hissing noise similar to what I hear when SUVs drive by me - it's the weird exhaust hiss that sounds mechanical. But I hewar it inside my car and it sounds like its coming from under my back seat, passenger side. There are some shimmys and some other things that I am sure are control and tie-rod issues. My question about those is, are those things I can tackle myself? I have worked on rock crawlers and trucks with varying success a lot in my life but they are tinker toys compared to this car. I'd be willing to spend the money on tools more than to have someone else do the work and charge me $90+/hr... Lastly, if i can't do the work on my own, is there anyone with advice on a good trustworthy shop in eastern LI? Thanks for the help! Mike

 

New tires = new tread patten = new humming noise? Check tire pressure re poor gas mileage. Different tread and tire composition can also affect gas mileage, although yours seems significant.

 

it could indeed be the new tires, but the mileage drop does seem quite high.where on LI are you?

 

The noise is there whether the car is moving or not, and seems to be effected by the cold weather - colder mornings = more noise... I may just take it to the dealer and at least get an estimate.

 

Yeah the drop in mileage is far more than anyone on TireRack seemed to experience with these Tires. I'm in Amagansett, close to East Hampton.

 

I just stopped at the dealer and it turns out its the fuel filter making the noise. Apparently it is a common thing to have that replaced around 80k too. So if you hear a whining, hissing noise coming from your back passenger seat coupled with a moan from your engine compartment when accelerating on cold mornings, you need a new fuel filter! And apparently, the fuel economy issue is due to an ailing thermostat that isnt letting the engine get to proper operating temp, and therefor forcing the injectors to run a rich mixture until the car warms up, using more fuel. It makes sense when it's explained, but I still have my doubts... Anyway, the $400they want to replace the thermostat will be better spent on a floor jack, manual and some parts at ECS, I think. Any pointers on DIY-ing a thermostat? Thanks for the replys, btw!
Mike

 

I just put 4 new tires (Fuzion HRi) on my 05 A4 1.8T with 61k and my mileage has not dropped.

On the thermostat replacement topic, while I have performed some work on my Audi before, bypass valve, brakes, etc, I may be more in favor of having the thermostat replaced by a mechanic (either via the dealership or a by local capable garage) since this type of replacement can be challenging. Just my 2 cents.

 

Thanks for the reply ptzdodge - I will definitely do a little research before i make the decision to undertake that thermostat. Sometimes it's easier to let them deal with the discarded coolant etc... plus the repairs are usually warrantied As for the tires vs mpg, I am hoping that the thermostat issue takes care of some of that. It looks like there is a small leak from the o-ring where teh thermostat hits the engine, too. I guess I am getting this done in the next few days whether I like it or not...

 

thanks for the update! i dont think fuel filter would have crossed my mind. did you go to Storms or some where else?

 

Ilackav8, yeah I went to Storms - on the upside they were able to have it done by the end of the day without an appointment. Downside - $213.00! Ouch. Do you bring your car to the dealer or is there another option for you up island? I ask because I used to drive 3 hours to get my car worked on in CA.