Willister86

Hello AudiWorld Forum,

This is my first post on this site. I’m looking into purchasing my first Audi. I’m trying to decide between a 2017 A6 (3.0 w/ 78,000 miles) and a 2017 Q7 (3.0 w/ 108,000 miles). Both are the exact same price. I’ve test driven the Q7 but have not with the A6. (It drove fantastic, FYI.)

Please forgive any ignorance. I’m wondering if the same 3.0 is in both vehicles. I’m assuming both have different transmissions. I’ve probably not been looking at the correct threads online, but, I’ve sort of been reading that some people say “stay away from the Q7” due to reliability issues but I’ve seen people encourage folks to definitely get an A6. So, what are the powertrain differences? Is one inherently more reliable than the other? Anything I need to know before making a decision? Relying on you Audi folks to help steer me in the right direction. I lean more towards the Q7 (Kids) but really want your input.

FWIW, I race late model asphalt stock cars and restore classic American vehicles as a hobby. I’m very mechanical and any work doesn’t really scare me off. I’ve previously owned bimmers, Lexus, etc.

Thanks in advance!

Wes

Mesquite77

In USA all models with 3.0L in 2017 are mated with 8 speed ZF (Audi Tiptronic). I.e., both cars you are looking at have almost identical drivetrains. Oil consumption is only thing to check. Cars driven in town, short distances seem to start drinking it, cars with higher miles on highways, not so much. Sure lots of peeps will have other opinions on causes (liker OCI), but that is how my cars behave (correlated to driving habits, not OCI)...

FrenchToast

There are two "danger" 3.0 drivetrains. One is the 4th and last generation supercharged 3.0 which would have been in a 2017 Q7, possibly a 2017 A6 but not sure. The second is the turbocharged 3.0 with 48V mild hybrid. The latter has nothing to do with the engine, but the 48V starter-generator.

The problem with the 4th gen 3.0 SC is that Audi removed one bank from the PCV system, perhaps in order to meet Euro 6 emissions at the time. This accelerates carbon buildup on the exhaust valves (intake valves have separate washing injector). There are several reports of exhaust valves burning out between 70-110k miles.

Most direct injection engines suffer from carbon buildup - the problem in this instance is the single-vented bank accelerates carbon buildup. The intake valves are kept clean with a washing injector, but the exhaust valves get coated quickly. 1st, 2nd, 3rd generations of the 3.0 SC have both banks connected to the PCV and it takes longer for carbon to build up on the valves.

Unfortunately the mileage you're looking at is definitely in the danger zone. Don't buy it without scoping the exhaust valves before purchase. Add compression test if possible. If history is available, OCIs should be more frequent than factory's 10k interval. Or you can just budget immediately pulling and cleaning the heads, but that isn't very economical. Check the threads below for oil consumption warning signs.

https://www.audiworld.com/forums/q7-...-year-3024173/

https://www.audiworld.com/forums/q7-mkii-discussion-211/oil-consumption-issue-crank-case-ventilation-3067799/

I would ask this forum if the C7 still retains both vented banks, or check the appropriate parts catalog. If you don't need to tow, also consider the Q7 2.0. I think the 2.0 ring issues were all solved by 2017.

hopkinsd21

To clairfy Mesquite77 respone, only post 2015 to I believe 2019 Q7 4M is a 3.0T with a ZF 8 speed. Pre 2016 is a ASIN 8 speed transmission. Two completely different trans. Same with Audi A6 c6.5 also.

After 2019, Audi went with 3.0 Turbo replacing the super charger.

Agree with French Toast. Read/Reseach about CREC Audi engines, seems to be cylinder #5 catastrophic issues around the 100k mark. Same engine that is in the C7 A6 as well. Does not mean all are subject, but definitely need to be cautious.

Q7 4L 3.0T does have more limitations due to they Simos 8m3 software, but way more bullet proof and longevity of an engine that the Q7 4M 3.0T. 4M Q7 have more performance and tuning capabilities, sits on more standard rims sizes and is easier to find parts at time, but tends to have way more maintenance and issue long term.

All of my 4M understand is purely from research when looking to buy a Q7. Ended up with a 2015 4L and have not regretted my decision.

Not sure if this info helps, but happy to answer questions.