Walnut blast for CREC?

[Spitfire007]

Having PCV and cold start idle codes.
Indy suggested a valve cleaning while the supercharger is off if I bring it in. No one has looked at it yet.

Does the CREC need that even though it has dual injectors?
2016 A6 3.0 with 84xxx miles


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[RLCree]

Not an expert, but my understanding of the CREC is no, that's not required any longer.

[sepheroth86]

I have heard of people with CREC still needing to have the walnut blast performed on occasion.

[Spitfire007]

Thanks, that's what I thought. Plus she gets the Italian tuneup once a week.

I'm guessing that I should have some other things done "while it's open"
-thermostat
-water pump
-coolant crossover pipe
-intake gaskets and other breather pipe/check valve pieces
-aux drive belt (not SC belt)


Anything else?
Hopefully no additional things like valve cover gaskets...



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[Mark.in.tulsa]

Tune your car to run on e85 and your valves will be clean......[:D]

[Spitfire007]

I would like an IE stage 1 and TCU.
I hear the TCU really makes a difference in daily driving.
But nooooo. Car needs maintenance, and when it rains it pours.


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[quattroism25]

This was mine at 120k when I did PCV and walnut blasting. You're already in there, might as well do it.

https://i.ibb.co/7JJZKS2/20200821-141924.jpg

[cadguy77]

This was mine at 120k when I did PCV and walnut blasting. You're already in there, might as well do it.

https://i.ibb.co/7JJZKS2/20200821-141924.jpgOn what car/engine?

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[quattroism25]

2012 A6 3.0t

[cadguy77]

2012 A6 3.0tIs that a CREC engine?

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[gk1]

Was there any noticeable difference power, drivability, gas mileage, before and after cleaning?
I think that Audi claims, while it may look bad, it does not affect anything until it gets much much worse.
I know the question will inevitably come back "How can it NOT affect anything?" and honestly, I don't know, but I do not recall seeing data points like either before/after cleaning dyno results or pre/post cleaning mpg figures for a few thousand miles.
I recall if it got real bad on the NA RS4/RS5 V8 it caused misses, but AFAIK anyone who has gotten a cleaning on a 3.0T didn't mention misfires before the cleaning it was more just done because the S/C was off kinda thing.

[Spitfire007]

2012 is not a CREC, it only has one set of injectors.

2016+ are CREC, and have dual injectors: thottle body injectors (helps clean backside of valves) and direct injectors (which don't).

I'm not sure how it will look when it all gets opened up, since I do drive it hard, and everywhere all the time. Hopefully I can get some pictures.


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[Dippy]

FYI CREx went into production in Summer 2014. I don't know when it came to North America but certainly it was only in cars like the A6 and not in the S4 or S5.
I have seen only a few CREx valve pics and so far all looked pretty clean in comparison to the older engines so I am under the impression that the dual injection is keeping the carbon low.
But the more pics we can get the better.

[MattyMarkey]

FYI CREx went into production in Summer 2014. I don't know when it came to North America but certainly it was only in cars like the A6 and not in the S4 or S5.
I have seen only a few CREx valve pics and so far all looked pretty clean in comparison to the older engines so I am under the impression that the dual injection is keeping the carbon low.
But the more pics we can get the better.

Came to the US for MY16; US Models C7.5 16+ have the CREC

[RLCree]

Came to the US for MY16; US Models C7.5 16+ have the CREC

Yup, along with the A8's and Q7's. Only 3 that got it from all the researching I've done.

[WatchMeSpend]

FYI CREx went into production in Summer 2014. I don't know when it came to North America but certainly it was only in cars like the A6 and not in the S4 or S5.
I have seen only a few CREx valve pics and so far all looked pretty clean in comparison to the older engines so I am under the impression that the dual injection is keeping the carbon low.
But the more pics we can get the better.

This ⬆⬆

[Spitfire007]

Car goes to Indy Thursday. If and when they open it up, I'll ask for photos.


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[JWebb_C7_Comp]

Car goes to Indy Thursday. If and when they open it up, I'll ask for photos.


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When I had my oil BMW (N54) walnut blasted while other work was being performed, my Indy sent me photos. It wasn’t awful at about 100k miles, but it needed attention. Gas mileage increased and idle was nearly silent once the WB was done.

That motor, however, was DI only. CREC isn’t and was supposed to avoid this issue. I’d definitely was to see whether the extra $$$$$ is sensible.


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[regulartalldude]

To confirm what some people have mentioned-
CREC was an updated version of the 3.0T, one of the updates was going from 6 injectors to 12. Therefore, carbon buildup occurs at a much much slower rate. I had my blower off a few weeks ago (55k miles) and while there was some crud, it was extremely minimal compared to equivalent mileage first gen (CTUB) 3.0Ts. I also run ethanol for most of the spring and summer which is probably making it worse than it would be with just 93 octane.

The odds that the issues you are experiencing are from carbon buildup are extremely slim. Unless you are seeing a loss of coolant, your PCV is probably fine. A lot of CREC cars have a PCV soft-code that can be seen when a full scan is completed from when the fuel-rail recall was completed but the unit itself is still fully functional.

I am located in the Philly area and do a lot of maintenance work on my own cars and friends Audis- let me know if you ever need something done for a better price :)

Edit: someone mentioned the coolant crossover pipe- this was another update on CREC that they replaced this plastic/rubber part with a metal one so it rarely fails anymore.

[Spitfire007]

To confirm what some people have mentioned-
CREC was an updated version of the 3.0T, one of the updates was going from 6 injectors to 12. Therefore, carbon buildup occurs at a much much slower rate. I had my blower off a few weeks ago (55k miles) and while there was some crud, it was extremely minimal compared to equivalent mileage first gen (CTUB) 3.0Ts. I also run ethanol for most of the spring and summer which is probably making it worse than it would be with just 93 octane.

The odds that the issues you are experiencing are from carbon buildup are extremely slim. Unless you are seeing a loss of coolant, your PCV is probably fine. A lot of CREC cars have a PCV soft-code that can be seen when a full scan is completed from when the fuel-rail recall was completed but the unit itself is still fully functional.

I am located in the Philly area and do a lot of maintenance work on my own cars and friends Audis- let me know if you ever need something done for a better price :)

Edit: someone mentioned the coolant crossover pipe- this was another update on CREC that they replaced this plastic/rubber part with a metal one so it rarely fails anymore.

Thanks for the insight. I'm also in Philly.
I don't think the car ever had a fuel rail recall done, and I've checked.
Found my dipstick cap was gone after the Indy did an oil change....could that lead to issues? I think so.
Hopefully it doesn't cause undue crankcase pressure issues leading to premature PCV or other failures.

Honestly I don't know how much more money I want to throw at this car, but it's a bad time to trade in for something else...
Needs brakes...
Probably shocks and mounts...

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[RLCree]

Thanks for the insight. I'm also in Philly.
I don't think the car ever had a fuel rail recall done, and I've checked.
Found my dipstick cap was gone after the Indy did an oil change....could that lead to issues? I think so.
Hopefully it doesn't cause undue crankcase pressure issues leading to premature PCV or other failures.

Honestly I don't know how much more money I want to throw at this car, but it's a bad time to trade in for something else...
Needs brakes...
Probably shocks and mounts...

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A missing dipstick cap would absolutely throw a PCV code. Also, just remember no matter what car you purchase, you'll always need shocks and brakes. Wear items are wear items. Good luck.

[WatchMeSpend]

Thanks for the insight. I'm also in Philly.
I don't think the car ever had a fuel rail recall done, and I've checked.
Found my dipstick cap was gone after the Indy did an oil change....could that lead to issues? I think so.
Hopefully it doesn't cause undue crankcase pressure issues leading to premature PCV or other failures.

Honestly I don't know how much more money I want to throw at this car, but it's a bad time to trade in for something else...
Needs brakes...
Probably shocks and mounts...

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If you want to replace it with similar but newer, could you even find one? If I put my car up for sale and then looked to buy another, the best car I could find would probably be mine. Very slim pickings, even if I go to an A8.

[Spitfire007]

If you want to replace it with similar but newer, could you even find one? If I put my car up for sale and then looked to buy another, the best car I could find would probably be mine. Very slim pickings, even if I go to an A8.

I'd much rather have a manual trans, so I'd be looking at other brands than Audi.
That said, a Giulia Quad could persuade me to try another auto trans, but I'm really not happy with this one. Clunky, slow, makes the car surge when I don't want it to and doesn't downshift when I want or quickly enough in manual.
I hate autos...


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[sepheroth86]

I'd much rather have a manual trans, so I'd be looking at other brands than Audi.
That said, a Giulia Quad could persuade me to try another auto trans, but I'm really not happy with this one. Clunky, slow, makes the car surge when I don't want it to and doesn't downshift when I want or quickly enough in manual.
I hate autos...


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Did you do a TCU flash?

The factory software is terrible.

[Mark.in.tulsa]

Did you do a TCU flash?

The factory software is terrible.

It is a whole new beast with a TCU tune.

[Spitfire007]

Did you do a TCU flash?

The factory software is terrible.

Not yet. I keep finding better places to put the $$$...


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[Audibellybutton]

You should honestly run a bottle of techron in the tank every now and then. You will actually reap the full benefits because you have dual injection. It will help with carbon build up and help clean the other components of the fuel system

[Thomas@TAI-VW]

PCV code is probably from solenoid valve on that later model. You can replace it without SC removal if you cut the hardline and splice it into the plastic pipe coming out of PCV assembly.

[AudiInMyA7]

To confirm what some people have mentioned-
CREC was an updated version of the 3.0T, one of the updates was going from 6 injectors to 12. Therefore, carbon buildup occurs at a much much slower rate. I had my blower off a few weeks ago (55k miles) and while there was some crud, it was extremely minimal compared to equivalent mileage first gen (CTUB) 3.0Ts. I also run ethanol for most of the spring and summer which is probably making it worse than it would be with just 93 octane.

The odds that the issues you are experiencing are from carbon buildup are extremely slim. Unless you are seeing a loss of coolant, your PCV is probably fine. A lot of CREC cars have a PCV soft-code that can be seen when a full scan is completed from when the fuel-rail recall was completed but the unit itself is still fully functional.

I am located in the Philly area and do a lot of maintenance work on my own cars and friends Audis- let me know if you ever need something done for a better price :)

Edit: someone mentioned the coolant crossover pipe- this was another update on CREC that they replaced this plastic/rubber part with a metal one so it rarely fails anymore.

I am also in philly. Would you be willing to chat about DIY stuff? I’m tryna get my hands dirty and do some of the work myself. Just replaced by rear pads/rotors to try and fix my car wobble that didnt fix anything [emoji24][emoji24]


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[AudiInMyA7]

It is a whole new beast with a TCU tune.

I can confirm. A simple stage one and tcu tune woke my car right up and now its a monster

Edit: everything is bone stock, no upgrades in engine parts or anything, just a tune and it was one of the best investments i did for my car

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[regulartalldude]

I am also in philly. Would you be willing to chat about DIY stuff? I’m tryna get my hands dirty and do some of the work myself. Just replaced by rear pads/rotors to try and fix my car wobble that didnt fix anything [emoji24][emoji24]


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