You need to get a manual oil pressure gauge that reads LBS. per squire inch so you can read what the oil pressure is for sure. Then remove the oil sending unit from the engine and screew the oil pressure gauge in it's place and start the engine and read what it says.
I would give you the oil pressure SPECS. and tell you where the sending unit is, but you did not say what year are engine size and what it is in.
If you have oil pressure it is working.
My guess is low or no oil pressure.
Could you tell me how would you replace the oil pump on a Mazda Protege?
No, if you have oil in your oil pan, you have other problems. It has nothing to do with your water pump going out or being bad.
No oil pressure
Remove oil pressure sensor and install a manual gauge
Low oil pressure or fluctuating oil pressure.
The oil pressure is dropping at this time. A clogged oil filter, clogged oil pump screen or failing oil pump can be the cause.
The oil pump rattling is very unlikely, a bad pump causing other components to rattle and damage themselves is VERYlikely.
No oil pressure - after checking with a manual gauge
oil pump is going to be 1 of 2 places. inside your oil pan, or where your oil filter attaches. never worked on a Dakota but have never seen a pump anywhere else. hope this helps.
The oil could be dirty or the filter could be clogged. The oil pump screen could be clogged or the pump could be going bad.