1997 Nissan Altima Oil Leak Front Engine Ive Put Bars Stop Engine Worked Also

I have an oil leak from the front of my engine. Ive put bars stop leak in my engine and it hasnt worked, ive also put an oil treatment in it. that slowed down the leak surprisingly. I want to do my own maintenance on my car so I know what to do if I have future problems. when I check the oil the dipstick reads full but the oil is very black, which means it time for an oil change, but I want to fix the oil leak before I change the oil.my heater also stopped working when my oil leak started.