Tim1

My 2012 3.0tsfi has been consuming 1 quart per 750 miles. Only 72,000 miles! I've replaced the PCV valve assembly with no improvement. I'm pretty certain that the low friction piston rings used in this engine allow the oil ring to get fouled with carbon. I did a liqui-moly motor flush followed by 1000 miles with new oil and 2 quarts of marvel mystery oil, then change and fill with new liquimoly 5w-40. Too soon to tell but it seems oil consumption is now 1 quart in 1250 miles, but not sure..on long highway trips consumption drops and I did a long trip after the flush. I've heard of people repeating the process 3 or more times, some have incredible results, some none at all. I'd love to know what results others are getting.

Pothole5000

This is my second 3.0tfsi Q7, and it is also a quart of oil every 600-700 miles depending on highway/backroads mix. My first one had about the same millage and it was only a quart every 5000 miles.

I also bought the liqui moly, and the flushes but am planning on doing it next weekend. Also I’m planning on doing another flush and change in 5000 miles instead of the normal 10k, see if that will save me from having to do the PCV.

'10Q7TDI_Prestige'

If the problem is actually related to the low-tension oil control rings, then yes. Do the LM oil flush, making sure you use the correct amount of product for the amount of oil your engine holds, and leave it in for the max time as noted in the directions on product. Also, you want to leave the oil in the vehicle longer so that the detergents in the oil can work at the deposits as well, just run reduced change intervals of like 5k miles, etc. FWIW, you may want to consider running the LM Top Tech 4200 5W30 LL in it rather than the 5W40 variant, as it is certified for VW 505 and also the 507 oil spec, which is a higher standard (for the TDI engines) than is the 505...it has more detergents/ability to clean the gunk in your engine out. Buy it in the 5L jugs for best pricing and to get the extra oil for top-offs...it's reasonably priced at FCP Euro, but many vendors carry it.

I used just a few liters of the Top Tech 4200 LM oil in my sister's Kia Sorento that suffers from heavy oil consumption, which is definitely the low-stiction rings problem on hers...a big problem with those Kia engines. Just adding a few liters to her car brought it back to life and reduced the oil consumption significantly; then they up and changed the oil one week after I had backfilled it with my LM oil stash for the TDI's, and just to prove the point that oil choice matters, after they drove on the lesser oil installed at the quick-change shop...dumping the new LM oil I had put in it, their consumption went back up again after driving on it for a couple thousand miles more. The next time I saw them they asked about what oil I used since they had noticed the major decrease in oil consumption right after I topped it off, and that was only with 2 Liters. Who knows if your issue is fully linked to the rings sticking, as there may be other issues, but worth a shot. Neither of our cars has ever used any oil unless there was a problem/oil leak related to a part failure, and we are at 120k and 115k miles on them, respectively.

imsolidstate

I've had a few audis with bad oil consumption from the rings being coked. Quart of oil every few hundred miles and a grey cloud behind you when you rev it. Tried a bunch of stuff, but in my opinion the only thing that actually fixes it without putting in new rings is an EPR flush. This is just what I do, use at your own risk. I'm a risk taker. On a cold engine add EPR to the crankcase and start it up. Once it's warm drive it for about ten minutes, shift manually so you can do medium acceleration and compression braking. You want to work the piston rings as much as possible with the solvent in. The solvent being hot is what makes it work. In my opinion if you just idle for 5 minutes like the instructions it's not as effective. And cold soaks putting it in the cylinders isn't effective either for the same reason. Change the oil and it will be super black. I did about three flushes on a 2.0 A4 and went from a quart every 200 miles to not needing to add any oil for 2-3k miles. Did a flush on a 4.2 that was burning oil on acceleration and it stopped, no more smoke cloud in the rear view (engine has 155k too). Now I do an EPR flush whenever I change the oil as maintenance.

bg_2007Q7

I haven't experienced any oil loss in my 3.6L, but I run the LM engine flush every oil change. Plus I add some LM ceratec to the new oil. Makes my engine purr...

FLOS5IN

How did you know you needed to replace coolant housing and therm?

Darianmeh

any recommendations on the EPR flushes you used?

'10Q7TDI_Prestige'

Recommendations? The EPR flush is a BG additives family product...Liqui Moly has their Proline Oil Flush products group, etc.

If you want to see results from any oil flush product, read the directions for use carefully and be sure to buy enough product to treat the amount of oil your engine holds; on a 4L Q7 engine (typically holds 8-9 Liters of oil) you will generally need to use two bottles of oil flush due to the higher oil capacity/volume, depending on product labeling, so read the product carefully and apply/use it correctly, as per product directions to achieve max cleaning results.

Please remember that the oil flush is a 'remedial' type of product to help remove accumulated undesired deposits, like gums and varnishes that result inside the engine from incomplete combustion of fuel, as well as the oil being diluted and broken down more quickly over time, as a result.

Oil bypassing the piston's oil control rings is likewise exacerbated by super-extended oil change intervals, which allows more combustion related gunk to accrue inside an engine between oil services, etc.

IMHO, the best preventative action you can take on these engines to reduce or prevent oil control rings capture/oil consumption is to buy high quality, top-tier fuel that comes with a minimum mandated amount of additives included. Use a high quality injector cleaner additive annually to maintain optimum fuel injection precision and combustion quality/control, and if you drive in mostly urban or heavily mixed driving, towing, or extreme climates, then reduce your oil change intervals based on how you actually use your car. And, of course use excellent motor oil/filters meeting the published VW oil spec requirements of your motor, etc. There is also still some truth to be had in the older car-guys reference to an 'Italian tune-up'; I'll let you look that one up.

Good luck!!