Water in the oil is a sure sign of a blown head gasket. Stop driving this car until you have this repaired or you will do serious engine damage.
Head Gasket blown, plus check your water pump.
Water in combustion chamber-common sign of bad head gasket especially if recently overheated. Oil will probably have water present in it and easily apparent.
So, ... what is your question?
blown head gasket
No changing the oil didn't cause this. Check to see that your cooling fan is operating.
That means your car overheated and you blew a head gasket. It happened to my 1995 prelude.
Could be overheated coolant or just leaked oil burning off your exhaust headers
I think a "top overhaul" will do. They will just change a gasket which prevents the oil from leaking into the water.
Oil yes. Sludge from overheating maybe not. Might be able to run some engine oil flush through the oil system and see if it cleans it out. Don't drive the car with it in the engine and change the oil twice after you drain it all out to be sure you get all of the kerosene out. Otherwise, you will end up with a locked up, overheated engine.
Check your oil and see if it is white/pink/beige/discoloured .... if it is, the head gasket blew when it overheated .... if the oil is okay, the fuel pump cutout may need to be reset (check owners manual).... and if that's okay, then disconnect your battery .... wait 1 minute .... then reconnect it and try again. The ignition module may have given up in the overheating and may need replacement.
Assuming you replaced the pump and all is well in the water department - there may be a connector, vacume hose orsomething disconnected when you did the work. Was it badly overheated. Replace the oil and maybe the trans fluids also.
When it comes to cars, oil and water don't mix. Oil has its own reservoir as does water.