Audi Q7 3.0 TDI catastrophic engine failure

[FreedomSpeed]

Hello everyone,
I’d be most grateful for any in-house expert views and also hearing from anybody who may have had the same experience. I bought a brand new Audi Q7 S Line 3.0 TDI a while back, in 2016. Just loved the car so kept it for years. In December 2024, the car was suddenly diagnosed a write-off after a catastrophic engine failure. Meanwhile:
- Car meticulously serviced at prescribed intervals, always at Audi garages
- In 2022, I had to replace the engine fan, which was done at an Audi garage, and everything ran seamlessly otherwise
- The last service including oil change was done in January 2024, by Audi as always
- In mid-2024, the car started showing coolant liquid leaks, which I was initially simply topping up but as it became more frequent, I had it checked at Audi garage and the car underwent an exorbitantly expensive coolant valve repair
- At the end of last year, and some 140 miles after the coolant repair, the car completely collapsed on me. It was the very first longer journey after the coolant repair… the car also underwent a health check at that point at the Audi garage
- Whilst driving on the motorway, a warning of “low oil pressure” came on. I stopped the car almost immediately when it was safe to do so… and it never started again
- Just before this happened, the car did feel a little off – the engine was not smooth and everything felt a little wobbly. Then the disaster struck literally within moments
- This was with 75k miles on the clock, 10k from the last oil change and just after being at Audi garage
- Audi garage then found metal shavings in the oil as a reason for the failure though was unable to explain how the metal shavings got there other than noting “a random degeneration” must have occurred within the engine
- The garage insisted that the coolant valve repair can in absolutely no way be connected to what just happened, though neither them nor Audi UK were able to answer how come this happened so shortly after the repair and how come the mechanics have not spotted anything unusual in a car that was about to die 140 miles later (whilst the customary health check was also performed)

I just cannot comprehend how this can happen with a perfectly maintained Audi... aside from there being a manufacturing/design flaw in the engine or negligence in the repair and/or servicing. I am now in the process of appointing an independent expert to inspect the car as well in order to better understand what went wrong and build grounds to hopefully hold Audi to account. I did everything to ensure the car can operate for years and years and now have a write-off car and what a waste on all the Audi garage bills paid to exactly avoid what just happened.

Any pieces of wisdom or advice hugely appreciated.

[GordonGekko]

Fitting a used engine and back on the road, surely?

[stevieturbo]

Not a nice scenario, but main dealers are not renowned for their abilities.

And not quite sure what a "coolant valve" is ?

A second opinion would be a good way to proceed, but there will probably be no cheap escapes.

Perhaps reach out to these guys ? https://www.youtube.com/@VAGTechnic ( assuming you're in the UK of course )

But without some sort of actual report, and status of the engine at present...not a lot of other advice out there

[KingGary]

And people say Land Rovers have dodgy engines. I feel smug knowing Audis are worse. Sorry that doesn’t help, hope you find a solution.

What I do know is most main dealers are no use and no guarantee of longevity. Sounds like you’ve suffered a mechanical failure.

[Hugo Stiglitz]

What gen is this, I.e. belt or chain- When was the pump or belt last changed?

I'd never leave a VW belt to their specified mileage or year change personally.

[stevemcs]

As above, watch some of the vag technic videos, chains and oil pumps are all too common on these.

[Sheepshanks]

I wouldn't dream of running a VW Group diesel without warrranty cover - just dumped wife's 8yr old 4Motion Tiguan that she had from new. Had the All In cover on that but stops at 8yrs and in its last year it had a few faults which All In took care of. Audi don't offer it on 3 litre cars.

I guess another way of looking at it, is you've saved a fortune by not taking Audi extended warranty - I just priced it up for a random Q7 and it quoted £1700. Maybe cheaper for earlier years but still would have cost a lot to cover it for the last 5yrs. And it might have been a lot of hassle to get them to pay out anyway.

If it needs a new engine then I suppose there's a remote possibility of goodwill but even if they gave you 50% the repair bill is likely to be immense.

[stevieturbo]

Hugo Stiglitz said:

What gen is this, I.e. belt or chain- When was the pump or belt last changed?

I'd never leave a VW belt to their specified mileage or year change personally.

They're all chains, at the rear of the bloody engine

[Hugo Stiglitz]

Sheepshanks said:

I wouldn't dream of running a VW Group diesel without warrranty cover - just dumped wife's 8yr old 4Motion Tiguan that she had from new. Had the All In cover on that but stops at 8yrs and in its last year it had a few faults which All In took care of. Audi don't offer it on 3 litre cars.

I guess another way of looking at it, is you've saved a fortune by not taking Audi extended warranty - I just priced it up for a random Q7 and it quoted £1700. Maybe cheaper for earlier years but still would have cost a lot to cover it for the last 5yrs. And it might have been a lot of hassle to get them to pay out anyway.

If it needs a new engine then I suppose there's a remote possibility of goodwill but even if they gave you 50% the repair bill is likely to be immense.

I thought that the 3l was generally robust with servicing? Darn that's my future used purchase gone!

[rambo19]

Sounds like cam chain tensioner has broken up.

[Maxdecel]

stevieturbo said:

Not a nice scenario, but main dealers are not renowned for their abilities.
And not quite sure what a "coolant valve" is ?

No knowledge of this PU.
Brief search and - https://differentcarreview.com/2023/04/29/2nd-gen-...
Video at the end mentions "Plastic coolant regulating Valve " @ 3:30 Stevieturbo.
Salient points I noticed - abundance of plastic parts used which do not appreciate the heat cycles of an engine, EG. the above valve & chain guides which I first heard of in Ford DOHC disintegrating.
Depends which generation but Cam sprockets/ metal contamination in oil ? Jumps teeth eventually(Rough running) then finally cries enough when the chain moves yet again and the inevitable happens?
Of course the contamination may have occurred after the engine destroyed itself, nothing can be established with any confidence without inspecting.

[joshcowin]

Hugo Stiglitz said:

I thought that the 3l was generally robust with servicing? Darn that's my future used purchase gone!

They are decent! I have one on 127000 and my father has one on 145000+ 13 plate Q5 and 10plate A6 respectively

I just keep it serviced every 6 months.

[njw1]

FreedomSpeed said:

Hello everyone,
I’d be most grateful for any in-house expert views and also hearing from anybody who may have had the same experience. I bought a brand new Audi Q7 S Line 3.0 TDI a while back, in 2016. Just loved the car so kept it for years. In December 2024, the car was suddenly diagnosed a write-off after a catastrophic engine failure. Meanwhile:
- Car meticulously serviced at prescribed intervals, always at Audi garages
- In 2022, I had to replace the engine fan, which was done at an Audi garage, and everything ran seamlessly otherwise
- The last service including oil change was done in January 2024, by Audi as always
- In mid-2024, the car started showing coolant liquid leaks, which I was initially simply topping up but as it became more frequent, I had it checked at Audi garage and the car underwent an exorbitantly expensive coolant valve repair
- At the end of last year, and some 140 miles after the coolant repair, the car completely collapsed on me. It was the very first longer journey after the coolant repair… the car also underwent a health check at that point at the Audi garage
- Whilst driving on the motorway, a warning of “low oil pressure” came on. I stopped the car almost immediately when it was safe to do so… and it never started again
- Just before this happened, the car did feel a little off – the engine was not smooth and everything felt a little wobbly. Then the disaster struck literally within moments
- This was with 75k miles on the clock, 10k from the last oil change and just after being at Audi garage
- Audi garage then found metal shavings in the oil as a reason for the failure though was unable to explain how the metal shavings got there other than noting “a random degeneration” must have occurred within the engine
- The garage insisted that the coolant valve repair can in absolutely no way be connected to what just happened, though neither them nor Audi UK were able to answer how come this happened so shortly after the repair and how come the mechanics have not spotted anything unusual in a car that was about to die 140 miles later (whilst the customary health check was also performed)

I just cannot comprehend how this can happen with a perfectly maintained Audi... aside from there being a manufacturing/design flaw in the engine or negligence in the repair and/or servicing. I am now in the process of appointing an independent expert to inspect the car as well in order to better understand what went wrong and build grounds to hopefully hold Audi to account. I did everything to ensure the car can operate for years and years and now have a write-off car and what a waste on all the Audi garage bills paid to exactly avoid what just happened.

Any pieces of wisdom or advice hugely appreciated.

'Coincidence' would be a good way of describing what's happened there IMO, also, I've had cars that have gone from seemingly healthy to dead in a lot less than 140 miles!

[Jakg]

FreedomSpeed said:

neither them nor Audi UK were able to answer how come this happened so shortly after the repair and how come the mechanics have not spotted anything unusual in a car that was about to die 140 miles later (whilst the customary health check was also performed)

I just cannot comprehend how this can happen with a perfectly maintained Audi... aside from there being a manufacturing/design flaw in the engine or negligence in the repair and/or servicing

Sometimes, everything is working fine until it's not. A healthcheck is superficial, it's not an x-ray of the engine. If Audi were going to guarantee the car for 8 years, that's how long the warranty would be - but they don't.

Nothing can last forever, *somethings* going to either wear out of break. It sucks, especially for a newer car - but I think your onto a loser expecting any contribution from Audi.

I say this as someone who has a car with a dead engine on the drive - it was fine... until it wasn't.

[Easternlight]

Maybe you've just been unlucky and some random tensioner,seal , bearing etc has failed.
Meticulously looking after a car doesn't stop it from going wrong sadly.

[OldGermanHeaps]

st happens, and with most brands. I have had peugeots, fords, vauxhalls, bmws, mercedes and renaults all having major faults well within their warranty periods, and a couple of catastrophic failures just out of warranty despite servicing exactly as per.
My best luck has always been with audis.
Audi dealers are st though, find a good indy and take it from there. You have proven how st by them fobbing you off with a "random degeneration" without making any attempt to find the cause.

Edited by OldGermanHeaps on Sunday 26th January 00:34

[Maxdecel]

Jakg said:

ometimes, everything is working fine until it's not. A healthcheck is superficial, it's not an x-ray of the engine. If Audi were going to guarantee the car for 8 years, that's how long the warranty would be - but they don't.

Nothing can last forever, *somethings* going to either wear out of break. It sucks, especially for a newer car - but I think your onto a loser expecting any contribution from Audi.

I say this as someone who has a car with a dead engine on the drive - it was fine... until it wasn't.

But "Vorsprung durch Technik" Superior engineering, etc, etc...

[E-bmw]

FreedomSpeed said:

I just cannot comprehend how this can happen with a perfectly maintained Audi... aside from there being a manufacturing/design flaw in the engine or negligence in the repair and/or servicing. I am now in the process of appointing an independent expert to inspect the car as well in order to better understand what went wrong and build grounds to hopefully hold Audi to account. I did everything to ensure the car can operate for years and years and now have a write-off car and what a waste on all the Audi garage bills paid to exactly avoid what just happened.

Any pieces of wisdom or advice hugely appreciated.

Basically it can happen in many engines differently, servicing is no guarantee, a health check is no guarantee and random coincidental failures do happen.

The coolant valve will almost certainly have had no effect as it is in the coolant system only & you had no coolant/cooling issues at the time of failure.

Your act of "appointing an independent expert" is potentially going to cost a lot of money as to produce any meaningful results they will have to at least partially dismantle the engine.

I would have thought if it was maintained as you say, your best route would be to push Audi UK for goodwill based on the fact that THEY had it in their hands so frequently throughout it's life.

[PushedDover]

Sheepshanks said:

I wouldn't dream of running a VW Group diesel without warrranty cover - just dumped wife's 8yr old 4Motion Tiguan that she had from new. Had the All In cover on that but stops at 8yrs and in its last year it had a few faults which All In took care of. Audi don't offer it on 3 litre cars.

I guess another way of looking at it, is you've saved a fortune by not taking Audi extended warranty - I just priced it up for a random Q7 and it quoted £1700. Maybe cheaper for earlier years but still would have cost a lot to cover it for the last 5yrs. And it might have been a lot of hassle to get them to pay out anyway.

If it needs a new engine then I suppose there's a remote possibility of goodwill but even if they gave you 50% the repair bill is likely to be immense.

Just put the warranty back on my 3L Allroad after 18mo of expensive niggles.
Same kind of price for a 2016, 96,000 miler

Plan to do this for a couple of years, but note you say there is an 8 yr cap?

[stevieturbo]

OldGermanHeaps said:

Audi dealers are st though, find a good indy and take it from there. You have proven how st by them fobbing you off with a "random degeneration" without making any attempt to find the cause.

I would say they would be too inept to find a cause.

Although at dealer labour rates, I certainly wouldn't want to be paying them to try and establish too much, as that alone would probably cost several thousand, and they'd still probably have no clue.

Videos like the above certainly don't inspire confidence, although the engine itself is used in literally hundreds of thousands of cars, Audi, VW, Porsche, so there are plenty of variants out there.

I have one myself, which so far has been all good although I'm only around 85k. A friend has one slightly older and has had some coolant leaks under the intake, and needed some injectors.
Coolant leak was a nightmare to fix, but not expensive in terms of parts. Injectors pretty easy too.