We've got a 2017 S4 Avant that went to the main dealer with a small oil leak. In their attempt to solve the leak, they completed a diagnosis, replaced the casings and seals around the timing chains, then replaced the sump ... then found a manufactured hole in the engine block that was leaking the oil ... and told us it now needs a new engine! Has anyone experienced any similar tragedy?

And here's a photo of the 'hole' in the engine block - any thoughts would be really appreciated.

I have no idea what the hole is for, but it does appear to have a plug in it. Is that plug metal or rubber? Does it have a hex top or slot to allow it to be screwed in? Whatever the reason for its existence there must be a way to seal it that does not involve another engine.

Hi Cliff  Thanks for the post - sadly, no plug in it and no-one including the manufacturer's technical department seems to know why it's there or what purpose it serves ... all ideas welcome.

Hello James,

If it were mine, I would be carefully measuring the diameter of the hole and searching for a suitable (tight fitting) plastic plug, and temporarily blank off the hole to see what happens. Take care that (1) the plug is a tight - ideally tapered fit - to ensure there is no chance of it entering the engine. (2) It can be removed without too much fuss. 
Perhaps you could let us know how you get on James.

Kind regards,

Gareth. 

1 hour ago, James Goddard said:

Thanks for the post - sadly, no plug in it 

Sorry, the black dot in your picture looked like a plug. Is the hole round or rough? Threaded or smooth? Parallel or tapered? Is the metal around it cracked?

How best to repair it depends on what the hole leads into. 

Speak to Tomas at VAG Technic. Oxfordshire to Dudley is about 1hr 30mins away. They drop performance engines all the time and know their way around S4. I’m sure there’s logical explanation.

Massive thanks to Richard aka Spartacus 68 for recommending Tomas at VAG Technic who is very familiar with this problem and can fix it 🙂

Please do tell us what the hole is intended for, and what needs to be done about it.

It appears that this is a drain hole through the block from the top near the turbo / oil cooler that drains down to the bottom of the block but doesn't actually enter the engine - assume it's to stop a build up of water / moisture on the top of the block.  The extreme heat from the turbo dries out the seals on the oil cooler, causing the leak.  The oil then flows through this drain channel and out at the bottom.  It therefore appears to be leaking from this hole, when in fact it's leaking from the oil cooler at the top of the engine.

12 minutes ago, James Goddard said:

It appears that this is a drain hole through the block from the top near the turbo / oil cooler that drains down to the bottom of the block but doesn't actually enter the engine - assume it's to stop a build up of water / moisture on the top of the block.  The extreme heat from the turbo dries out the seals on the oil cooler, causing the leak.  The oil then flows through this drain channel and out at the bottom.  It therefore appears to be leaking from this hole, when in fact it's leaking from the oil cooler at the top of the engine.

So basically fit a new oil cooler? Audi we’re going to charge you £20k+ for a new engine!

Might be worth fitting upgraded oil cooler and investigation additional heat shields around the turbo.

I hope you will not be returning to the thieving sharks at Audi who wanted to sell you a new engine.