1966bronco

I own a 2014 Audi A7 with a 3.0 TFSI Engine. I’m familiar with the carbon buildup issues with these GDI engines. My A7 has 75,000 miles and I’m starting to notice a rough idle or a shiver when idling. I’ve tried fuel injector cleaner with no improvement. Spark plugs are new but I have not replaced any ignition coils yet. No codes thrown yet. My inclination is that this is a symptom of carbon buildup on the intake valves and I would like to do some preventative maintenance. I’m debating between a solvent cleaning (like CRC Intake Valve & Turbo Cleaner or Seafoam SS-14) or a manual cleaning using either brushes/pics or Walnut Blasting.

A bottle of CRC or Seafoam runs about $15. I’ve used the CRC Intake cleaner on my 2015 GMC Yukon 5.3L with 90,000 Miles, also a GDI engine. It significantly reduced (if not eliminated) the rough idle that was persistent since I bought the vehicle with 50,000 miles. This was done two weeks ago and so far, so good. Here is a post that suggests NEVER doing a solvent cleaning and supports the manual cleaning https://www.audiworld.com/forums/a6-...2909914/page2/

I’ve shopped around and it will cost about $1,000 for a shop to do the cleaning. This is very labor intensive as the Supercharger needs to be removed (among other parts). I feel that I am mechanically inclined enough to do this myself but I would be a lot more confident if I could find any video or written instructions.

My worries with the solvent cleaning are:

• The CRC mentions spraying the solvent into the throttle body past the mass air flow sensor, but I can’t seem to find a mass air flow sensor, if this engine even has one.
• If I spray directly into the throttle body will the solvent do any damage to the supercharger?
• Will the thermal shock of running the solvent damage the catalytic converter, or will chunks of carbon dislodging from the intake damage the catalytic converter?

My concerns with a manual cleaning are:

• I can't seem to find a video or written instructions for removing the supercharger and intake manifold to expose the intake valves. I did find a video for a Thermostat change on an S4 which has a 3.0 TFSI (
  You Tube
  ). This might be close enough.
• If I’m going to go through the hassle of removing the supercharger, what other items should I service or replace:
  • Thermostat
  • PCV Valve
  • Supercharger Oil

Any advice would be well appreciated.

boghy

On my 2012 A7 witth ~95,000 miles on it i used this:


crc intake valve and turbo cleaner. The car runs much more smooth. In addition i switched to Liqui Moly HT, and that oil burn from exhaust disappear completely. Toke me about an hour and a half. I toke my time on with that can.

1966bronco

Thanks for the reply. I'm leaning toward the CRC Intake Valve Cleaner. Glad to hear it worked for you.

boghy

In my case, i changed the oil 20-30 miles after doing that CRC cleaning. To be clear, on the can does not specify after how many miles to change the oil, so that's subjective for interpretation. However, they do recommend changing the oil after such cleaning process. So i did mine when i was about 5,000 miles in my old oil. I used to use Castrol EDGE 5w-40 from Walmart, that thing creates a oil burn smell and after 5,000 miles i lost 0.5qt oil. So now, with liqui moly part# 2332, the smell went away and i do seem to get better gas mileage. Not to mention the car runs better. In other words, low NOACK on oil DOES MATTER for these cars.

1966bronco

I've done the CRC on my Yukon. I had to make sure that I injected it past the Mass Air Flow sensor. I'm guessing that the A7 doesn't have a MAF. Did you just simply stick the hose in the air intake like Boghy did in his picture above? No Check Engine Lights? How long ago did you do it? And did you notice a difference?

boghy

I personally went very slow with that can.
What I did not do: have the engine at 2,000rpm
What I did do: leave it on idle, and spray it in small increments.
Toke several brakes, since the job was lengthy, which is why likely is stated 2,000 rpm to shorten such process. I'm not saying that's right or wrong, but after an hour and a half and several cold drinks here in South Florida, the can got emptied. All this time I left the engine running at idle.
Drove about 50 miles, changed the oil and ever since then I drove the car like I stole it. Literally.
No VCDS engine errors whatsoever.
I am not a mechanic, but after 800 miles after that job, i can truly say that the car runs much smoother than before.
In addition, my only issue is related to a complete battery drainage that I posted on another post, which has nothing to do with this job. Which is not a priority for me to fix it due to Florida weather. I hope that helps.

1966bronco

That does help, thank you.

36dbldz

Can you take a pic of what hose you put it into please, hard to see

boghy

This is for quick reply:


The key here is to reshape that can hose. Have it shaped with a heat gun or some source of heat to look like that red graph. It will fit through that vacuum hose after being disconnected.

Jonbishop32

Bump on this older thread, I have a 3.0t TSFI Q7 and am wanting to do this, did it come out good for you two?… anyfeed back will be awesome