Audi Oil Consumption Issue: Is Your Audi Drinking Oil?
We have noticed an uptick of high oil consumption in Audis. Some customers are adding a quart of oil for every 250 miles while factory spec is an unacceptable 1,200 miles. We believe that well-maintained cars with less than 100,000 miles should not consume oil between oil changes.
Something is wrong.
We have found three common causes for abnormal Audi oil consumption:
- Oil leaks
- Failed crankcase vent valve (PCV)
- Clogged piston rings
We have developed a protocol to help reduce oil consumption. Most of the time it is effective, however, if any of these three items are neglected or too advanced, sometimes the issues are terminal.
Oil leak repair is paramount in preserving the longevity of all engines. Most often, and if you are lucky, the upper timing cover and cam magnet seals leak. The repair for these leaks is a gasket, two seals and an hour or hour-and-a-half of repair time. Complexity and repair time increase significantly from here.
Your dad’s first car had a PCV valve, which evolved to a crankcase vent valve. As the engine runs, pressure builds inside it and oil mixes with air. The vent lets the pressure out and keeps the oil inside.
You can test your crankcase vent valve quite simply. Start the engine and let it idle then, with the engine running, unscrew and remove the oil fill cap. A faulty valve will create vacuum pressure and pulling off the cap will be difficult. You will have a hard time lifting the cap off if the crankcase vent valve has failed. You might also see excess soot or oil residue at the tailpipe. The crankcase vent valve is also an easy repair and takes less than an hour.
- If the engine pressure is not vented, issues will arise (item 1 being most common). If neglected, seals will be compromised as the pressure fights to get out…
- If the oil is not retained, it is like a leak. It goes out the tailpipe and you have to refill. You can also check this–is there black soot inside your tailpipe? Is it powdery soot or oily residue? Oily usually indicates item 3.
Piston rings can be problematic–sometimes we can clean them so they seal better and reduce oil consumption. Sometimes they are not repairable. If the car has had frequent oil changes at quality shops (i.e. not quick lube shops that use low-quality oil), it is more likely to improve with these measures.
In either outcome, our process is to start with a quality oil change and ring cleaning engine flush. For the oil change process, we’ll use a top-shelf oil like Castrol or Motul’s ring-formulated oil. For the ring cleaning, we use the BG 3-step for this and have had favorable results. We also use BG 3-step on BMW’s cam actuators–Audi owners should not feel alone…
Then you drive your car and evaluate the results. With luck, it will improve, although we’ve never seen it return to as-new performance.