you are saying "the car is 21 years old, mileage 23000km" but I think you mean it's a 21 year model with 23000km. and you have to add 80-90 grams after 5000km which I think is about a cup of oil...now this might be normal because of the oil you use and of course how you drive and the climate temp. you live and drive in and I suspect the engine is burning it cause you don't see any leakage...here in Canada we're told by Hyundai to use 0W-20 Quaker State Synthetic 3.8L oil and it suits our year round climate...maybe you should at least use Synthetic oil which I would have thought that Hyundai would want to be used for a 21 model...years ago when I had my 73 Corvette I had the 454 engine and it went through about a quart of oil about every 800 miles and this was normal for GM big block engines and of course back then there were no Synthetic oil and 10W-30 was the norm back then.Hi all.
The car is 21 years old, mileage 23000km. I noticed earlier and even after changing the oil that after a run of 5000 km, about 80-90 grams of oil burn out. Should a new car use oil?
I fill in good oil Total 5w30 A-5
everywhere around is dry and nothing drips
this is just a guess on my part for the reason of your consumption.