Then, when engine is also cold, check coolant / radiator level. There should also be a hose running from radiator to an expansion tank, I'd make sure this hose is not blocked, and also the ends where the hose connects onto are not blocked. Coolant will not be able to go through it, if the hose is blocked. This will lead to the coolant eventually boiling over to much and either blowing out of the radiator cap or radiator nipple. I'd also check that the radiator cap is sealed to.
Your oil being black and you saying you haven't changed it in awhile means only it is overdue for service. Get you car a fresh LOF. It overheating is another problem. This is a big problem. If the coolant is boiling, it most likely means you have a blockage, a thermostat stuck closed or sticky, a poor or plugged radiator either internal or external, or a coolant fan motor inop. You're going to need some diagnosis here.
The oil would have nothing to do with that. It sounds like your engine is over heating. Check the coolant level and add more antifreeze if needed. You should mix pure antifreeze 50/50 with water or else buy the pre-mixed kind. Of course, you may have something wrong with your cooling system, like a slow leak or something else, but check the coolant level first.
Could be a few things. You could be low on coolant, leaving enough space and low enough pressure for the coolant to boil. Or the thermostat needs to be replaced causing coolant flow issues. Also, don't put off changing your oil for too long, the longer you wait, the harder it gets on your engine.
Also, make certain that the front of the radiator is not blocked by anything, I. E. plastic bag, dust, or cloth rags.
Your thermostat need replacing.
I use my cat for a hour and today was hot when I turn off my car my engine sound like it's boiling water. My oil is black I haven't changed it because I haven't had time. Could it be that?
