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auditech79 12-08-2008 09:40 PM

Gas odor
Some of you may have noticed that there is a gas odor coming from the outside of your vehicle and on occasion on the inside of the vehicle. Its most likely a problem thats not easilly diagnosed that i discovered 4 years ago that applies to 97-04 A6's with all available engines. Most technicians replace the large O-ring for the fuel pump or fuel sender which is located under the rear seat. 90% of time thats not the cause of the leak and or smell.
About 4 years ago i had problems diagnosing a gas odor from both the inside and outside of the vehicle on a 3.0L A6. I found a few drops of gas on the floor after it sat over night but i could not see where the leak was coming from. In order to find the leak i had to remove the entire rear end and drop the gas tank out. What i discovered was 4 EVAP lines attached to the top of the tank, two of which has broken off. The reason the lines broke off the nipples on the tank was because a small steel insert had backed out the fitting causing it to bend with the movement of the car, eventually breaking off the nipple and causing a leak after topping off the gas tank. It will still leak if you are driving with a half full tank causing the gas odor. Replacement of the gas tank is the only cure for this condition which is a very expensive repair. I have since replaced 50 gas tanks for the same condition and i have heard from my friend at the dealer that there may be a recall out for this condition now. I sent several pictures to audi over the years trying to get it covered for you guys, but i had no luck while i was still working at the dealership. I would check with your local dealership and ask if there is a related recall for repairing this issue, or at the very least buying an extended warranty that will cover this repair.

If you have any questions about the issue you can PM me.

Edit: oc audica supplied this recall statement from volkswagen:
but the recall appears to only cover 01-04 which i believe should take care of it since audi has probably done more research on the issue. I can't remember the year models i worked on but i do know i have replaced tanks on 2.8L,2.7T, 3.0L and 4.2L's. The 4.2L A6 doesn't appear to be in the recall as of right now, so hopefully that will change. Better yet i could be wrong about the 4.2L altogether and you 4.2L owners won't have a problem.

oc_audica 12-08-2008 10:18 PM

there was a recall on a valve nipple, iirc, that required dropping the tank to fix ~ it applies to all 01-04 A6 iirc.

i have the same problem right now, sadly my 99 doesn't qualify under the recall and I don't have the funds to diagnose it (thinking it costs at least $500++ ??)

jag0214 12-08-2008 11:57 PM

I'm dealing with this now too. First, the dealership said that it was a valve cover gasket leaking oil. Next, it was coolant flange leaking coolant, oh, and might as well throw in a timing belt (+ kit), water pump, thermostat, and who knows what else while we're at it. Spent my Christmas budget on various 'fixes' (okay, some was just standard maintenance, but not as important as me making it to work without passing out!) all to no avail and now I'm back at square one. I guess I didn't do a good enough job describing the problem - my own fault really.

Just came in from the garage after removing the rear bench. I thought I would try to check the o-rings for a leak myself before doing anything else. I'd obviously be interested in a recall so please keep us posted. Thanks.

nm3210 12-09-2008 01:15 AM

Can you give any more specifics on detection? Because my gas odor is only when in conjunction with the exhaust, otherwise i don't smell anything out of the ordinary.

oc_audica 12-09-2008 06:18 AM

i half pass out from the fumes on the highway.. sucks

it barely started around 180k

whitey 12-09-2008 04:29 PM

Originally Posted by oc_audica (Post 1005510)
it barely started around 180k

awesome - I'm at 188k now with no smell (keeping fingers crossed)

nemohm 12-09-2008 04:40 PM

There is some recall bay Audi Canada (I received the letter, but never had the time) in relation with fuel tank nipple or something. (I have to find the letter).
As far as I remember the specified time to fix it is ~1h.
Could that be the same as described issue?

auditech79 12-09-2008 08:19 PM

Memohm, you should post a copy of that recall here so i can see what audi has for a fix to see if it coincides with my repair. It may very well be the same repair. What im thinking audi is gonna have the techs do is loosen the straps that hold the gas tank in place and let it hang on the rear axle, then opening up the service ports under the rear seat and trying to access the two front nipples from the service holes. However you wouldn't be able to reach the rear evap nipples that way.

BUDDAH 12-09-2008 10:12 PM

Hey Im having this same problem with my '98 A4 (67xxx mi) and i was wondering if the A4 also had problems with EVAP lines? Thanks.

auditech79 12-09-2008 11:42 PM

Originally Posted by BUDDAH (Post 1005960)
Hey Im having this same problem with my '98 A4 (67xxx mi) and i was wondering if the A4 also had problems with EVAP lines? Thanks.

Nope, you're looking at the gas cap or the filler neck assembly most likely.

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