jmsurpri

Had my 2012 A6 3.0T serviced recently. They did oil change, replaced the 'cylinder head temperature sensor' which caused check engine, and also did a carbon cleaning. They also did the fuel line recall and PODS recall. My mileage is way down after getting the car back. Haven't gone through a full tank yet, but it's looking like I may get ~200-250 miles per tank. I've always gotten > 300 miles regardless of how I drive. Performance feels about the same. No gas smell in garage. No change in driving, just to and from work as always.

One interesting thing I noticed right away is that my car takes much longer to get up to temp (to 4 tics on the gauge). Previously it would get to temp pretty quickly, maybe within the first couple miles of driving. Now it's about double that. Outside temperatures not much different compared to before service. Also another interesting thing is when I filled up the car, the miles remaining gauge showed 385. Ever since I got the car, it's always showed ~445 after a fill. I always assumed this was some static (gallons * rated mpg) calculation so it was odd to see a smaller number there.

I checked for faults with VCDS and found nothing. Does anyone have suggestions on how to diagnose this? Anything I can look at in VCDS? After getting a sensor replaced, does the car need some time to recalibrate?

SCarGuy

it is very common for a car to take a tank, or two or even 3, to fully get back to its ideal settings once services like this are done, especially since the battery was completely disconnected.

jmsurpri

Thanks for the feedback. I guess I'll just wait and see if it improves over time. Does anyone know how I can query the value of the 'cylinder head temperature sensor' in VCDS? I want to see if that new sensor is functioning properly.

gk1

What kind of carbon cleaning did they do? A full remove the supercharger and walnut blast the intake valves? or just a spray in cleaner?
Reason I ask is perhaps there is a leak somewhere if they remove the supercharger, but most likely it is as mentioned that it will just take time to re-calibrate.

jmsurpri

They removed the supercharger and did the full cleaning.

Acuransx

jm, how many miles on your car and if you don't mind me asking was this work done at the dealer and what did it cost? The "hope" among many on AW is that in the later years of VAG DI engines carbon buildup is a thing of the past (I have a /15 3.0T) but somehow I think this is wishful thinking and that without secondary port injectors we are all headed to where you have recently been insofar as carbon cleaning is concerned.

Best,
Jeff

jmsurpri

52K miles. Service was done at a local Audi dealership. Cost is an interesting discussion. They removed the supercharger to replace the temperature sensor. That's when they saw the carbon buildup and suggested a cleaning. They said that since the supercharger is already off, they would offer me a *discount* and do the cleaning for *only* $950. I said thanks but no thanks. Eventually we agreed on $500 to do it, which I think is still too much, but I was told it takes them quite a bit of time to do the cleaning since it's a slow manual process.

Acuransx

Thanks for that information. Anyone who thinks carbon buildup in the 3.0T is not going to be an issue is likely to be disappointed. Having to do a carbon cleaning to an engine with just over 50K miles for approximately $1,000 is not progress IMHO. My spare car (04 Acura TL owned since new with now 171,000 miles) runs pretty much as new and engine has never been opened up, doesn't use any oil, doesn't leak a drop and I'm pretty sure if engine were torn down would be clean as a whistle compared with some of the pictures of what our 3.0Ts look like with the carbon/coking issues that are a part of living with our modern DI engines.

While I really enjoy my A6, the issues I have had in the first 3.5 years combined with the carbon buildup and attendant need for a "cleaning" at higher mileage dictate that my A6 will be gone by the time it reaches 6 years/65,000 miles, if not earlier. I'm just not willing to risk engaging in the fun and games of German luxury car ownership beyond 6 years/65,000 miles -- too many expensive things that can go wrong. I confess I'm living in the past to some extent. Japanese cars of the 90s up to mid-2000s were pretty simple and bullet proof (with a few exceptions) -- given that they have become more complex they are probably not as reliable as the old Acura.

Best,
Jeff

porksoda

One of the ECU recalls that they did causes mileage reduction, check your receipt you will see it... i will put in the recall code here soon.

Here is the thread: https://www.audiworld.com/forums/a6-...tware-2907293/

DanfZX14

I can attest to this being true. Such BS Pisses me off....

Still love my car though! The Audi Corp not so much.