Help Please 2014 3.0 V6 CREC issues

[Cjman17]

So, car is a 2014 with the CREC engine on about 54k, has an MRC stage 2 with crank pulley, running 470bhp.


Last week after my normal 30 mile drive to work I noticed a little vibration at idle, scanned with VCDS, showed no codes.


Took it out for a bit of a more spirited drive, logged a cyl 5 misfire, swapped plugs/coilpacks around, misfire stayed on cyl 5. Compression test came back at 150psi for cyl 4 & 6, cyl 5 only 75 psi.

Leakdown test shows valves are all sealing correctly, also with the charger off looking into the ports it all looks very clean. Air is escaping into the crankcase. So it's got to be either rings or a piston issue. Surprising considering its only done 54k miles.

Car is currently at my mechanics 3rd in the queue for a rebuild

Anyone else had similar issues? What were the causes?

Also while it's bits what else should I have done? I don't want to get it fixed and back on the road only for something else to go in a few weeks time.

Other than PCV, waterpump and thermostat is there anything else worth doing?

 

[g00se]

Gutted for you Chris.. this is my worst nightmare, I was told these engines are pretty bulletproof (bar the odd known fault). How long has the car been Stage 2, and do you think its at all related? I also presume the car is regularly serviced ?

I selfishly ask as I'm going stage 2 next week and this makes me a tad nervy...

goose

 

[Cjman17]

Not as gutted as me haha, cheers.

It was mapped in the middle of October last year, probably done about 2500 miles on it since, I don't feel like it's anything to do with the map, plugs were all in good condition showing no signs of running hot/lean. MRC have done plenty of these to know what's what so just a coincidence as far as I'm concerned.

I'm having a hard time convincing the wife though, it's all my fault for 'messing' about with it

It was on longlife oil when I got it in April last year, had done 42k and been changed 3 times, I wasn't too concerned with the lowish mileage but maybe it has had something to do with it.

Had a full major service done and switched to liqui moly oil when I got it and the oil that came out was still in decent condition.

Used about a litre in 4000 miles which I didn't think was too bad considering how I drive it!

I've spent a bit of time googling and this sort of issue on the V6 seems extremely rare. Just my luck I guess. I'm interested to see what the cat on that side is like, maybe it's blocked and cylinder 5 took the hit first due to it over heating quicker as it's in the middle!

My mechanic has a V8 S5 and an RS5 to do before mine so it'll be a while before I find out.

 

[Dippy]

There have been a fair number of reports of the previous engine "using" oil and that has usually been a PCV issue. The PCV was redesigned for the CREC and I can't remember seeing any other CREC reporting oil usage. Mine certainly doesn't although I have only done 23K ish miles.

 

[Cjman17]

Yeah i'm going to get him to do the pcv, might aswell, it's going to be small change compared to the rest of the work

 

[Cjman17]

Should be making a start on it properly this week, bought some bits to cheer myself up!

 

[Cjman17]

Looks like it's new piston time

 

[Cjman17]

All pistons are now out, injectors all tested.

All of the pistons seem to have quite a bit of burning/blowby, I'm starting to think that maybe this is down to poor servicing before I got the car.

Any opinions?

 

[ninjag]

Can't really comment other than to say I just changed my oil again after about 7,000 miles / 7 months of mainly local driving and the old stuff was pretty bad. Not only much blacker than expected (especially for a petrol and compared to cars like my Honda Accord 2.4 in the past) but rubbing between finger and thumb felt like the oil was not far off done (again, compared to other instances). The short journeys probably don't help, but I'm also wondering do these engines run quite hot because it certainly feels like it when I open the bonnet! lol

 

[Cjman17]

Yeah I think I'll be changing it every 5k from now on!

I think they do run pretty hot, you can even feel the heat coming from under the car from the exhaust when you step out of the car after its been driven hard!

 

[ninjag]

I just wish they had put a little service flap in the undertray for doing oil changes. The 3rd Gen Honda CRV has this, makes life so much easier.

 

[Cjman17]

Pistons finally arrived and rebuild is in progress at last!

After further investigation piston number 5 has a little bit more damage than we initially realised, luckily it didn't give way while it was running!

 

[Dippy]

Pistons finally arrived and rebuild is in progress at last!

After further investigation piston number 5 has a little bit more damage than we initially realised, luckily it didn't give way while it was running!

Is this showing a large piece of the piston is missing? If so it suggests a manufacturing defect.

 

[Cjman17]

Is this showing a large piece of the piston is missing? If so it suggests a manufacturing defect.

Yeah, there is a big chunk missing between the rings.
My mechanic was still a bit confused why the little bit of skirt that was missing on the other side was causing such a big issue with it being on the bottom and technically on the wrong side of the rings to cause a problem.

When he was giving it a bit of a clean and having a poke about that chunk just fell off!

 

[Dippy]

If I were you I'd contact Audi UK and request a failure analysis for that piston. You'd have to persist past those who don't know what an FA is and those who tell you to go away, and maybe you'd need to mention that publicity about a piston fault which could have caused a catastrophic engine failure would not be great for Audi's reputation, but I would like to believe that there are people at Audi (likely in Germany) who would genuinely want to have FA done. The net result for you might be nothing but it might be more, even if that is just information. You'd don't have much more to lose by doing it - you've lost enough already!

 

[Cjman17]

I've never really considered that tbh, I'm not sure if they would even entertain it with due to the fact it has been remapped.

I suppose its worth an email, would be nice to know if it was a fault with the piston even if that's all I got out of it!