quote:
I'm very surprised 1 quart per 1,000 miles is considered okay. That's a manufacturer who'd would have trouble getting my money.
Actually, per the manual it's 1 liter per 1k km, so about 1 quart per 700 miles. That number is high and does apply to realistic oil consumption at high RPM as often encountered in Europe. All my cars drank oil when driving Autobahn at 200 km/h for extended periods, but needed much less when driving in the city or on the highway. Oil consumption also increases if you tow for example a boat or a camper. The 1 l/1k km figure is not unrealistic. This number does not mean that the engine is allowed to consume that amount of oil right out of the box at all times!
Until 70k miles, my Audi consumed about 1/3 qt oil per 10k miles. That number was very low for an Audi, and the dealer and my independent Audi mechanic found this figure hard to believe. Oil consumption has increased with age, and in my opinion, it is mostly due to worn valve stem seals, seals which at 9 years old cannot be expected to be in excellent shape. If my car were to have the 30 valve instead of the 12 valve motor, I would expect even higher consumption! The way I drive my car has a huge influence on consumption! If I were to shift up all the time at 3000 RPM, my oil consumption would drop considerably. Alas, I rarely shift before intake manifold switchover (to shorter runner) occurs at 4100 RPM and I routinely redline the engine.
My cars with the worst oil consumption were a Chevy Celebrity ('85) and Buick wagon ('84). Both needed about a quart every 500 miles.
The 2.8 12v engine has low-tension rings. The oil rings are only 1.5 mm, which seems narrow. I know a guy who has his engine rebuilt with gapless rings. His oil rings had collapsed at about 150 k miles (Tuned 12v engine, makes 1/3 hp over stock). The pistons have been milled to accept 3 mm oil rings. The people who rebuild his engine said the stock oil rings on the 12v engine were undersized.
Anyway, I will see oil consumption comes down, following Terry's suggestions.