Quart and a half Quart and a half
put in 4 quarts, run it about a minute, wait a few minutes for the oil to drain back into the pan & check it. if it's a little low, add another half a quart or full quart depending on how low it is
No. And Yes. Why do you think it is low? Take an accurate reading and see if the level is at the "low" or "add" line. If so add 1 quart and check again. If you are sure it is still low add half a quart and re-check. But by this time if you need 2 quarts it would make more sense to just have the oil changed.
Yes
Yes, you can mix them.
About half a quart.
4 and a half
Book says 8.5 quarts. Almost dead on. I put in 8 after an oil change and ran it a week. Checked it and it was half a quart low.
These are common for oil pan gaskets, if the oil level is a quart low it most likely isn't high enough to leak out the gasket
quart and a half
1 quart and a half
Your dipstick is showing a quart low because the oil level in your engine is below the recommended level. This could be due to oil consumption by the engine, a leak, or simply needing an oil change. It is important to top up the oil to prevent damage to your engine.