99 pre-facelift 1.8T Quattro Manual, 70K miles

I noticed a humming coming from what sounds like the back of the car, I can't distinguish a side. It almost sounds like tire noise, but its noise I've never heard from the car, and it just started one day, so tire pressure is not the likely cause. It is dependent on speed, and it happens in any gear and neutral, clutch in or out. When I come to a stop, it goes away, and the engine seems fine, all fluids in tact, no strange puddles in my garage, ect. I noticed today that there is a faint, synthetic burning smell, it smells exactly like a hot glue gun. It seems to come from the front driver side wheelwell, but its hard to pinpoint. It could also be coming from underneath the car. I think these two problems are linked because I keep very close tabs on my car, and they have appeared within 24 hours of each other.

Recent service history
-both front wheel bearings replaced
-Just installed forge splitter last week
-front brakes and full fluid swap a month ago
-the bolts on the front passenger inner CV joint were loose and flinging grease around the underside of the car, I just had the shop re-tighten the bolts, they said everything looks fine.

Sorry for the lengthy discription, I'm just trying to be as detailed as possible. Any ideas?

 

how about a rear wheel bearing? i've had to change two since i've had mine...both on the right side.

i had a similar smell in my car a few weeks back. turns out after i changed the tb one of the covers was rubbing up against a pulley and it melted through the plastic. my own fault...guess i didnt put it on correctly. i doubt if this is your problem too though. good luck

 

bump... please help!

 

I'm having the same problem with a humming sound coming from the right rear. I'm thinking it is the right rear wheel bearing. I'm going to check it out this weekend when I have time. Mine definately sounds like tire noise too, but thats not it.

 

If you have a humming accompanied by a smell, then it usually indicates something is rubbing and consequently burning.

 

The noise from the rear definitely sounds like a wheel bearing. Do you think your valve cover gasket is leaking a little bit of oil, which would immediately burn off and cause that smell?

 

I would agree with this guestimation. Rear wheel bearing noises are certainly not out of the ordinary, especially at your mileage.

As for the smell, look for burning grease. Any time an axle is rebuilt or resealed, there's sure to be grease stuck somewhere. CV grease is incredibly difficult to clean.

 

Thanks everyone for the input, I have to agree on the wheel bearing. I jacked the car up, and there is no play in the rear wheels, but there wasn't any in the front wheels either when they both went bad.

Ok, the car goes to the tuner on Monday, I'll see what he says. I had a slight discovery though, if i'm sitting still and I saw the wheel back and forth from lock to lock about 6 times, the smell is much stronger. Could this be power steering related? That would explain the mineral oil-ish smell... I don't see any puddles or anything on the ground, I'm hoping that a power steering issue doesn't kill my bank roll, I was saving money for a chip, now I have to use it elsewhere, which sucks.

Any other input?

 

Did you check the level on the power steering fluid? You could be burning up the pump... better take care of it if so.

 

Well, I always keep a very close eye on all my fluids, but I checked anyway, and It seems to be right at the max fill line... I'm usually pretty intuitive with cars and problems, but this one has me stumped. I'll let you all know what I find out. Thanks to everyone who has responded!

Any other ideas?