97 nissan sentra..... recently changed radiator fan & battery... car turns on fine.... when parked , i turn car off but engine and fan continues to run

Don't run your ad or defrosted. That will over ride the shut off

Hi. Your radiator fan motor may be seized. Should ingage between 95-100 degrees when you parked on idle after achieving full working temp. If it doesn't, check fuse first and than relay responsible for cooling fan( you can find cavity in your owner manual. Let me know. The reason you car is ok while driving is the air going thru your radiator. When you stoped or parked for longer time with no speed there is nothing to cool your radiator. Fix it asap or eventually will cause engine over hit and seize.

Duplicate question.

if the gauge is staying at c even when u drive it it wont over heat or the fan wont cut in its not getting hot enough

You have 2 Problems, First problem batteries dying you have to make sure connections secure and alternator is charging your batteries (go to an Autozone or Discount advanced they will tell you). The Sputtering is either a bad SPARK PLUG or a damaged Cable going to the spark plug..Change them every 2 years.

Have it towed DO NOT RUN IT !!! Likely what you are seeing is engine oil in cooling system. (you will likely have coolant in oil as well, and a blown head gasket.Removing the oil fill cap you may find similar residue there) Antfreeze is not a good lubricant and can damage crankshaft bearings.
Did the engine overheat or run very low on coolant (reason for change of pump)? If so the head gasket problem was caused by that.

is it a manual or automatic?if it's manual check clutch.if it is automatic check transmission fluid.

One of the common things that gets missed at times is the radiator is down in cooling antifreeze. The car will act as normal during the warm up cycle and then the temperature guage will rise and then it will slowly come back down as the thermostat opens and/or the electric cooling fans come on. In actuality the engine is overheating, but it is not boiling over. The level of abtifreeze is at just the right level of lowness that you experience this phenomenon. After the engine cools off , (DO NOT REMOVE WHEN HOT - YOU CAN GET SCALDED WITH BOILING WATER/ANTIFREEZE)), remove the radiator cap and check the level within the radiator and also the antifreeze reservoir level. You can buy a 50-50 mix of antifreeze and water that is ready to put into the radiator. If the level in both the radiator and reservoir are correct, you may have a bad thermostat or some other problem.
Bob - 2003 Nissan Sentra SE-R SPEC V

radiator fan or the heater fan????