Oil level dipstick question

My early 1949 8N leaks a little oil. Not much, but a little.
How low on the dipstick can it get before I need to add oil.

It has 3 lines on it with crosshatching between them.
The top line is the full level and I know not to overfill it.
When it gets below the middle line I pour a quart in it.
I probably go thru one quart every 4 or 5 weeks.

What's the bottom line for.

Is it ok as long as I keep it between the top and bottom lines.
It is not practical to keep it at the full level all the time.
That would be ideal, but I keep watch on it and fill as needed.

Thanks.

Pooh Bear.

Or keep doing what your doing dispite the good abvice Dell and the others gave you, your call.

Pooh Bear

You doubt? Calibrate it nextime you change oil & filter. Full should be 6-qts. Pour 5-qts in and start the engine to fill the oil filter. Turn engine off after 1-min running and wait 1/2hr for all splashed oil to drain into the oilpan. NOW see where a known 5-qt quantity measures on yer dipp'em-stick. Then add yer final 6th-qt, and checker-again. Simple, eh?

Wannna quess what happens to yer engine oil iff'n ya overfill it? Pumps it out the breather, front and rear crankshaft seals, and yer crankshaft whips the engine oil into mayonnaise. (which is good for polishing little girls pattent leather mary-jane's) but not fer being sucked up by yer oilpump and lubricating yer crankshaft bearings. Itza 5-qt oilpan, (+1-qt in filter) it can tolorate underfill more better..... ..Dell

But as long as I keep it above the middle line I'm safe.
Good to know.

Thanks Dell.

Pooh Bear

It leaks oil the most when it is hot.
Leaks around the front mainseal somewhere.
I can see it drip when I shut down and get off it.
Going to straight 30 weight oil helped a lot.
Moving up to 40w would probably almost stop the leak.
It hardly leaks at all cold that I can tell.
I'll keep watching it and keep it between the lines.

Thanks.

Pooh Bear