Used to consume about .5 l (.5 qt) between oil changes. About 7 months ago, this consumption increased signficantly so that I am now adding a litre (1 qt) every 800 km (500 mi) or so (the level on the dipstick drops to about
1/8" below the bottom mark and then seems to stop there). There has never been any sign of oil leakage under the vehicle and there is no visible sign of 'smoke' out of the tailpipe. Any idea what might be causing this accelerated consumption of engine oil?
I have also recently had to replace my catalytic converter (media broke down inside the 'can' and started to rattle around ('check engine' light now on about 80% of the time).
Thanks for any help/suggestions.