It depends on year, make, model and the climate, consult the drivers manual.
I clicked "Improve answer" but I do not consider this an improvement of that post, I agree, just want to add my 2 cents. A fully synthetic oil is much better for your car. it lasts longer, lubricates better, tolerates heat better, the viscosity of the oil gets to the proper "thickness" far more rapidly than petroleum based oil. 90% of engine wear occurs upon start up, before the oil is pumped up to the top end and synthetics have additives that keep a film of oil on the top end for better lubrication on start up. Brand does not matter, I am not 'pushing' any oil. Mobil 1, Castrol Edge, Amsoil, and others For most cars 5W30 is good. Toyota recommends 0W20 in the newer Corollas. But I agree 100% with the OP, check your owners manual, and sometimes it is written on the filler cap.
what is a good engine oil to use in my car
Use what the manufacture suggests. Consult the owners manual for the correct oil for the engine.
The engine dipstick is the only tool you can use to measure how much oil is in the engine.
so the car engine will perform using oil.
No, you cannot use ordinary car engine oil. Use a JASO MA or MA2 approved oil, or SAE SF or SG graded oil.
No
No, not unless you want to destroy your engine.
The engine oil to use depends on the type of engine (diesel or petrol). See the car manual to know the exact oil reccomended by FIAT for your car
Yes you use engine oil in all cars regardless of transmission.
Yes
Depends on what engine is in this car. Use the 5W-40W grade fully synthetic engine oil. For gasoline engine check that the oil is A3 spec. For diesel engine, it should be B3 spec.
on car with 200,000 or and does not oil added after 3000 use 10-30 if car over 200,000 and use oil use striaght oil 30-40 weight