Viktor wrote:

> Guys, thanks a lot for your responses.
>
> Here are the details that I failed to mention.
> 1. My Honda Civic CX 97 has 160 000 miles on it.
> 2. After I changed the oil last time (and the oil level was above
> "Full" line directly after changing), the oil level has dropped to
> BELOW the "Add" line after I drove 3000-3500 miles.
> 3. Other then the drop in oil level I don't have other concerns. The
> milage is great (5.9 L/100 km - I am in Canada), no blue smok, just
> passed my emission test recently.
> 4. No leak of oil detected anywhere.
> 5. Don't know what PCV valve is, will find out.
> 6. When I detected that the oil level is less then "Add" mark, I
> poured about 1L of oil (I guess, about 1 quart) and it's full again.
>
> Thank you very much for all your help.

pretty much normal for a "mature" engine like yours. the PCV is worth a
shot tho.