Audi S6 engine failure

Audi S6 engine failure

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Discussion

Matt_E_Mulsion

697 posts

24 months

Monday 26th October
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The alarm bells ringing in my head regarding this tale is that the car gave a warning that it required oil shortly before it stopped running and the service manager at the garage commented that the oil level was 'very very low'.

Could it be possible that the problems are related to it being starved of engine oil?

catman

2,190 posts

134 months

Monday 26th October
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Even if you take the view that all 8 of the injectors needed replacing, they still charged the OP to remove the engine/gearbox to do it, when it's highly unlikely that it was required.

Elliot2000

736 posts

135 months

Monday 26th October
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catman said:
Even if you take the view that all 8 of the injectors needed replacing, they still charged the OP to remove the engine/gearbox to do it, when it's highly unlikely that it was required.
They will have access to Audi approved repair instructions and Audi job times that will give guidance on how they believe jobs should be done and how much time they believe it would take - these will be what they work too - i think the garage would be extremely foolish to try and overcharge for work on a job that was always likely to have a goodwill request to Audi to cover some of the costs.

Also most modern German turbo v8 and v6 engines are hot vee and therefore the intake side of the heads are quite low down on the sides of the engine close to the chassis legs which could make it very hard work to remove all the injectors without dropping the engine.

cmsapms

671 posts

203 months

Monday 26th October
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This link has quite a bit of info regarding S6 fuel injectors/system:

Audi S6 injector info

particularly the last couple of pages. Amazingly, engine out is the only way to replace injectors; brilliant design! There are also quite a few things that the "motor engineers" in the OP could have checked, but appear not to have done, like fuel pressure checks and hanging their noses over the oil filler hole!

It sounds like the S6 C7 can rapidly become a money pit due, in no small part, to design deficiencies.

My sympathy to the OPer!

stevieturbo

15,087 posts

206 months

Monday 26th October
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Elliot2000 said:
The engine was obviously not rebuilt in the way you are implying and it’s clear from the way it’s been described.

Injectors can and do just fail - maybe not entire sets in one go together - and this point I agree to that extent with you, but it’s also unlikely one failed injector will cause an engine to stop running altogether too - and the op did describe the car feeling down on power prior to the breakdown. Again we haven’t got all the info - it’s plausible more than one had failed and stuck open and allowed too much fuel pressure to be lost. It’s also plausible that Audi request that injectors have to be changed as a set and the main dealer is doing as it’s made to do. But after replacing one set of components,plus the spark plugs, the engine was then running - how is that a parts cannon repair?

Non direct injectors can be refurbished, direct injection solenoid type injectors can be refurbed, but a very modern direct injection petrol engine probably doesn’t use these - it probably uses piezo type which aren’t easily repaired and very few places do them .

Not every main dealer is out to rip you off
You surely know there is no logic in what you are saying ?

You're assuming that because the engine now runs....albeit incorrectly and they are still saying it needs more parts, that they did the diagnosing and repair competently.

Plus how the engine got from a low oil warning, to all the injectors failing and needing replaced...makes zero sense either.

If you had ever diagnosed any vehicles, you would understand this is not a reality.

Let's face it, none of it makes sense, especially on a low mileage car.

I'd most certainly be wanting the old injectors back and sent for testing at a bare minimum. These are the property of the owner. And if they test good, the dealer and whoever is doing this work, have some serious questions to answer.

RobbyJ

888 posts

181 months

Tuesday 27th October
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Have they checked for the dreaded turbo oil screen being blocked. It sounded from the start more like this issue to me.

Megaflow

7,279 posts

184 months

Tuesday 27th October
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cmsapms said:
This link has quite a bit of info regarding S6 fuel injectors/system:

Audi S6 injector info

particularly the last couple of pages. Amazingly, engine out is the only way to replace injectors; brilliant design! There are also quite a few things that the "motor engineers" in the OP could have checked, but appear not to have done, like fuel pressure checks and hanging their noses over the oil filler hole!

It sounds like the S6 C7 can rapidly become a money pit due, in no small part, to design deficiencies.

My sympathy to the OPer!
Is it direct injection? If so that partially explains having to remove the engine to swap injectors.

It might also explain the connection to the low oil pressure if they are oil lubricated.

Elliot2000

736 posts

135 months

Tuesday 27th October
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stevieturbo said:
You surely know there is no logic in what you are saying ?

You're assuming that because the engine now runs....albeit incorrectly and they are still saying it needs more parts, that they did the diagnosing and repair competently.

Plus how the engine got from a low oil warning, to all the injectors failing and needing...makes zero sense either.

If you had ever diagnosed any vehicles, you would understand this is not a reality.

Let's face it, none of it makes sense, especially on a low mileage car.

I'd most certainly be wanting the old injectors back and sent for testing at a bare minimum. These are the property of the owner. And if they test good, the dealer and whoever is doing this work, have some serious questions to answer.
Well over a decade as a senior tech, so I have done plenty of diagnosis on vehicles — and that has taught me it’s not always straightforward.

If u had ever diagnosed cars you would also know that the dealer has more information than the op or yourself right now - like the fault codes that were logged and what tests they have done to get to the point of recommending injectors.

The oil top up warning could be of some importance or it could be just a periodic top up being required - this may have been looked into or not - we do t know. It could be stuck open fuel injectors has washed the bores and diluted the oil to such a degree it’s tricking the level sensor - again we don’t know.

If a car comes in non running then their is limited amount of things that u could check. The garage had a non running engine - they found the component that was causing it to not run and replaced it - it now runs. Now they have managed to get it started they have heard an issue with it which they could not have known before as it was non running - now this noise could have been their for the last 2000 miles or not and the op may not have recognised it as an issue.

Car came into garage - garage used unknown amount of diagnostic techniques to come to a conclusion of why they believe it wasn’t starting- they replaced the items and it now starts- now it’s showing an issue in it’s running state and they have reported it to the customer - show me the illogical part of that process?

Are you really saying the injectors didn’t need replacing based on what you have read? Do you think just topping up the oil was all it needed? Because that is illogical

You are coming to conclusions without all the facts, i am giving a view based on what info we have been given


I hope the op gets it sorted and if she wants she can request the diagnosis info and report and take it to someone for a opinion on it


stevemcs

4,951 posts

52 months

Tuesday 27th October
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I think sometimes the downside to main dealers is they follow a set procedure to diagnose something, yes they have access to more material but sometimes that can be misleading.

What you normally find with cars is at first you fix whats broken, you then need to go and find what caused it to break in the first place and fix that.

stevieturbo

15,087 posts

206 months

Tuesday 27th October
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I am giving the view based on the reality that all the injectors simply do not fail. It is illogical, implausible...and just ridiculous really.
So in your experience...have you ever seen it happen, on any engine ? ( with the only caveat of someone using a totally inappropriate fuel...which has not been mentioned here )

But the only sensible course of action for now bar a full independent assessment ( which will include the injector test ), is having those injectors tested.

And any payments made for these "repairs", hopefully will be on credit card, so there is a hope that in any dispute, they can also offer support.


England87

193 posts

56 months

Tuesday 27th October
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I feel for you OP, unfortunately this is yet another example of poor Audi service with a ‘laptop says...’ expensive repair strategy. I would get the car out of there as fast as possible to a decent independent garage and try to argue paying as little as possible to Audi as they haven’t resolved the issues, if they even know what they are.

Edited by England87 on Tuesday 27th October 18:14

CAPP0

17,002 posts

162 months

Tuesday 27th October
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stevieturbo said:
I am giving the view based on the reality that all the injectors simply do not fail. It is illogical, implausible...and just ridiculous really.
So in your experience...have you ever seen it happen, on any engine ? ( with the only caveat of someone using a totally inappropriate fuel...which has not been mentioned here )

But the only sensible course of action for now bar a full independent assessment ( which will include the injector test ), is having those injectors tested.

And any payments made for these "repairs", hopefully will be on credit card, so there is a hope that in any dispute, they can also offer support.
I'm with Steve here. It annoys me intensely that main dealer workshops, in the main, simply plug the car in, read what the display says, and replace that component regardless of how large, expensive, or indeed irrelevant that is. It's entirely possible in this case that there was indeed an injector fault stored in the diags (the OP stated lower power before the breakdown) but there could well have been a second, unrelated issue (the Low Oil message is a big red flag) which is why the engine failed. If oil pressure had been lost but then the car sat for a good long while before the injectors were (spuriously?) replaced, then, assuming they actually had the nous to add oil without the OBD telling them to, the engine may well have run again, but badly.

I do a lot of my own maintenance (and for context, in the past 45-odd years, there's pretty much nothing I haven't rebuilt on a car, (and I mean rebuilt, not unplugged/unbolted/replaced) and I've also successfully converted cars to run completely different engines and transmissions) but where a job is beyond my skills and/or facilities I'll always go to an independent, where I know the people working on my car will know what they are doing, and more importantly why, rather than just waving spanners at the part which the computer tells them to.

Elliot2000

736 posts

135 months

Wednesday 28th October
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stevieturbo said:
I am giving the view based on the reality that all the injectors simply do not fail. It is illogical, implausible...and just ridiculous really.
So in your experience...have you ever seen it happen, on any engine ? ( with the only caveat of someone using a totally inappropriate fuel...which has not been mentioned here )

But the only sensible course of action for now bar a full independent assessment ( which will include the injector test ), is having those injectors tested.

And any payments made for these "repairs", hopefully will be on credit card, so there is a hope that in any dispute, they can also offer support.
I’m not saying they have all failed at once, I’m not even saying car is fixed. I was explaining firstly we don’t have all the info. Secondly- if they are piezo injectors they may well be of a type that the manufacturer recommends changing in sets (so a main dealer would have to recommend as per the manufacturer), or they are known to be an issue so changing just one or two wouldn’t make sense considering the level of labour involved changing them - although if this was the case it should be given as an option for the customer to decide if they want the set or individual injectors replaced.

And just so you know - I have seen defective batches of injectors fail on engines where we would definitely recommend changing the full set - early n53 and n43 bmw engines. And in that instance, even when out of warranty - manufacturers recommendation was to ensure injector index numbers were the same across banks.


stevieturbo

15,087 posts

206 months

Wednesday 28th October
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Again, the only sensible course of action for now is having the old injectors independently tested.

As you say, anything else is speculation.

I would agree that after testing if all proved to need replacement due to the work involved, all should be replaced.
But doing it without testing them, is mental.

KungFuPanda

3,727 posts

129 months

Wednesday 28th October
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RobbyJ said:
Have they checked for the dreaded turbo oil screen being blocked. It sounded from the start more like this issue to me.
Good point that a lot of people here have ignored. It''s a 10p size fine gauze filter which is situated close to the turbos that can get blocked and starve the turbos of oil. Not sure how common a problem this is but there has been a revised part and an after market relocation kit. Some owners have removed the filter altogether.

I've recently bought a 2015 Audi S6 privately. It is currently on 53,000 miles and in July of this year, the previous owner had spent £5k at Awesome GTI on an engine out replacement of both timing chains and associated tensioners and guides. He also had one of the two high pressure fuel pumps changed as well. Apparently, one of the plastic timing chain guides failed which threw the timing out. The car displayed an engine management light and ran on reduced power. The owner got it sorted and given it was done at a well renowned specialist, I had no qualms in buying the vehicle. To be honest, the engine should be running sweet as a nut for a fair few miles now. This may or may not be the same issue as you are facing.

wave_watcher

Original Poster:

32 posts

1 month

Wednesday 28th October
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Thank you to everyone who has taken time to reply. I’m better informed and hope to get some more support from the dealership. They’re planning on turning the engine over tomorrow afternoon once it’s all back together. Cross your fingers for me.

stevemcs

4,951 posts

52 months

Wednesday 28th October
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Good luck and take some lube

wave_watcher

Original Poster:

32 posts

1 month

Wednesday 28th October
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I asked for a few things when the dealership rang to say they hoped to have the car fired up tomorrow (and tentatively ready to come home from ITC). Before I accept the car back I've asked if they have changed the turbo oil screen (is that the right terminology)? Also I've asked for a print out of all the diagnostics. When I asked for the parts they have removed to be given to me they said it was likely the fuel injectors and spark plugs (removed during phase 1) had been disposed of already, furthermore, as the dealership is bearing 70% of the parts cost for phase 2, they won't release the old parts for phase 2 to me. I asked if they would as a minimum share photos showing the components which had failed evidencing any visual failures. I quizzed the need to replace the spark plugs only 7k miles after last serviced by them in Dec 2019. The guy said it was probably done if the plugs had been damaged as part of the initial break down problem. I'm not keen to pay the massive bill until I've had the local independent Audi garage look at the diagnostics. However, I realise I'm probably dreaming if I think the dealership will release that info before I settle up......

Andy RV

217 posts

89 months

Wednesday 28th October
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Does it have a history of using oil? If it was serviced recently to this event you / they need to establish the excessive oil consumption.

Replacing injectors etc won’t help you in the long run if it’s drinking oil due to another serious issue which they don’t seem to be considering.


Fuzzy69r

114 posts

42 months

Wednesday 28th October
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RobbyJ said:
Have they checked for the dreaded turbo oil screen being blocked. It sounded from the start more like this issue to me.
You beat me to it but normally if this was the start of the issue then you would have heard the turbos whining their heads off , not sure if the OP can recall any strange high pitched whines ? .

I really do feel for the OP as it certainly sounds like the usual main dealer approach of just throwing parts at it instead of doing a proper systematic approach to diagnosing the problem ( this can sometimes happen due to dealer workload pressure / only paying for so much diagnostic time etc but it doesn’t excuse it ) , being a ex main dealer merc tech this was one of my pet hates and one main reason I left the trade.

Can the OP get a breakdown of what they have done diagnostically and what’s been changed and why before going any further especially if they have done anything major to the engine internals and you’re now expected to pay for their fk up