Abcaudi

My sensor seems to be on its way, not sure so i have looked around to see how it should be replaced if that day will come and there are only bad news that the engine needs to be dropped.

I was thinking if it was possible to change the sensor A) without dropping? B) cutting inside on the passenger footwell by first remove the carpet then cut the aluminium in a place that is close to the sensor. Replace O2 sensor then weld it back again.

If possible it would be a lot cheaper then dropping engine, less work and no visibility after the surgery.

Any thoughts?

It is on a Audi S8 2007

MP4.2+6.0

Search. Look for a post by PaulW as one possible. He is on QuattroWorld more; rarely here. IIRC he had to do one on an S8; maybe one or two others too--who could have left the forum.

Abcaudi

Thanks found PaulW, it seems that he did it on a V8 engine, i need it on the V10.

I will search more now that you told me that there are people who have done it.

MP4.2+6.0

The V8 was his D2 and he used to post a lot more back then. He has a V10 D3 S8 more recently. Here is one thread I found. https://www.audiworld.com/forums/a8-.../#post24543835 Kind of bounces between pre-and post- cat O2's, but text definitely says along the way he did a pre-cat one that ultimately solved his issue.

Abcaudi

Thanks for the link, i have already read that, but it seems that he did on bank 1 which is the more accessible, Bank 2 and bank 4 is the hard ones that should have engine dropped which i hope should not be necessary, on this particular sensors i only have found incomplete threads that never told how the sensor replacement should be made.

Abcaudi

Any tips or advice?

MP4.2+6.0

Not for S8. Manifold set up is different than W12. On W12 all the forward ones are accessible from underhood, and easier at margin than 4.2. Rears on W12 are the "step 1, remove motor" problems.

You need to try to track down someone who has actually done it, specific to a D3 S8. No one has actually cut the body that I know of BTW for these kinds of hard to access things, though a few have threatened it in semi jest. More likely would be some dropping/supporting the subframe (with motor still in place) to get at things better. There have also been a few posts on complete S8 motor pulls with a bunch of gory pictures, if seeing the manifold out of car (w/ motor) would help somehow.

1Wasserwerks

​​​​​​​Are you pulling any codes yet? I have been able to get to banks 1 and 3 no problem from underneath. I currently have an issue on my bank 2 but it is due to a cracked exhaust flexpipe. I should be able to mock something up and weld in place before the winter. Are you hearing any leaks or is the sensor going wonky? Might have to do an engine drop unless you really want to start cutting things. It's quite possible that route would work. Welding it back might be a big pain, aluminum likes to be very clean.

Abcaudi

I got codes P2234 intermittent , P2187 , P0430 , P2189 intermittent
P1081 , P1085 , P0300 , P0305 , P0304

There are some small exhaust leaks on both pipes, marked in the red circle.

I get misfire in cylinder 4 and 5 and after reading there are symptoms for the oxygen sensor b2s1.

Dropping engine for small parts is not worth it for a 10 year old car, and cutting in a older car does not hurt as much so it was a thought if it was possible then it would maybe be a solution for the O2 sensor replacement.

Okey about the welding i would let a proffesional do it, i do know nothing about welding, i wonder if the O2 sensor would be accessible in this way

MP4.2+6.0

At least for me, codes are just alphabet soup. Look up/post the description that goes w/ them if you want feedback.