It will tell you on the oil fill cap. A GM 4.3? You did not specify.
You can use any SAE certified engine oil in your Nissan. The engine oil should be a 10W-30 weight engine oil.
40 weight
5w20 weight.
No, absolutely not, that is the wrong weight oil for your Civic. Use 5w30 weight oil. You can use a full synthetic but use the correct weight if you want this engine to last.
No, use only the weight oil as recommended by the manufacture.
the weight of oil viscosity weight is strictly related to temperature of operation. there is no set rules for it since anew engine will benefit from less dense oil an old wore out engine will not.
10w30
5W30 weight.
10w40 Motorcycle oil
Use 4 cycle oil if the engine is a 4 cycle engine. Use 2 cycle if it is a 2 cycle. Use the weight oil recommended by the manufacture of your ATV.
No , you should use what is recommended in the owners manual
Yes, use exactly what the manufacture recommends in the engine and gearbox. gearbox oil is normally a much heavier weight of oil.