Rear Differential Oil Seals

[darthweasel]

Hi

It looks like my car is leaking oil from one of the oil seals where the drive shaft goes into the rear differential. Is this a big (as in expensive) job, and are any special tools required?

It's a 2001 A6 Avant 2.5Tdi quattro sport.

Thanks.

DW

[darthweasel]

After further investigation it looks like this is actually a diesel leak that is getting onto the diff casing/drive shafts.

Assuming the actual fuel tank is sound, are there any other likely sources of this leak?

Does anyone have a picture of the fuel tank and it's location in the car?

[Peter D]

Yes I have. I need your email address either via PM or post up your email address, put a few spaces in it to fool the phishers. Regards Peter

[darthweasel]

Peter D

PM'd you although I'm not sure it worked.

I've been told that the problem is the seal on the fuel pump. That's got to be better than the initial diagnosis.

I'm having a new seal fitted tomorrow, hopefully that will cure the leak and also improve my fuel consumption . . .

The garage also asked when the filter on the diff(s) was last changed - I have no idea as the car has been service by my local village garage (ie not a VAG specialist) for the last 3 years - is this something I should be concerned about?

[dan.taylor.1]

Its not a Haldex system its a Torsen one so it doent have a filter, unless im mistaken!

Dan

EDIT - have you checked the filler neck, most fuel leak problems stem from cracked rubber or loose clips on the filler in my experience. HTH

[darthweasel]

Fuel pump seal and gasket has been replaced, leaked diesel cleaned up, looks good so far.

[darthweasel]

Quick update.

There were no further leaks until I filled up with diesel, then there was another pool of fuel under the car. It's been back in with my local VW/Audi specialist for the last three days - apparently it was a crack in the fuel pump (which is plastic), so a new pump was needed at a cost of £255 plus fitting plus VAT . . . joy . . . let's hope that's fixed it as we are heading for the south of France at the end of the week on holiday . . .

The good news is that it passed it's MOT with no advisories, a decent result for a 100k car.

[Peter D]

Ooooch. Regards Peter

[dan.taylor.1]

Out of interest did they not bother to check the pump while changing the seal?

Dan

[darthweasel]

I think there was so much diesel everywhere it would have been difficult to spot. Fair play to them, they spent a lot of time on the car and didn't charge much labour.

Average fuel consumption in 150 miles since the replacement pump is over 35mpg - I have never seen that sort of number in the time I have had the car. Previously I struggled to get 31mpg even when taking it real easy, so perhaps I had been losing fuel for ages. I've always thought the car smelled a little bit 'dieselly' outside, but as it is my first one I thought it was normal.