About 20 000 km (13 000 miles) ago I switched to Mobil 1 from dyno. I have done two other Mobil 1 changes since then. The engine is getting noisier (this also happened with our other car after a switch to a synthetic) and the engine is eating Mobil 1 at a rate of 1L per 2000 km (1 quart per 1300 miles). Before the switch the engine was quieter and there was no oil consumption. Also, in Canada, Mobil 1 is about three times as expensive as dino. I am thinking of going back to dino and keeping the change interval at 5000 km (3000 miles). The questions is: What are the warning signs that the engine is developing the sticky valve problem? How was this problem overcome in the newer cars?

92-960, 195 000 km (121 000 miles)