Every car needs a certain type of oil. The manufacturers usually tells you what kind of oil to use. Putting 10w30 oil in a 2005 corvette could really hurt the engine but putting it in a 1999 to 2004 Chrysler 300 M is perfectly acceptable. Considering you didn't say what model of car, this question is very hard to answer. The simple answer is to use the oil grade recommended by the manufacturers of your car.
What year is this car? I suggest using Pennzoil 10w30.
10w30 if using regular oil. I recommnd Spectro 10w30 clutch saver oil.
It shouldn't hurt anything until you get into the colder months. But, 5w30 is the recommended oil for that car. 10w30 is also a suitable oil down to 0*F.
It depends on the situation. Personally, I wouldn't use 5w20 instead of 10w30 for a complete oil change. However, using it to top off a quart or two shouldn't be an issue. Oil shears over its life so a little thinner oil shouldn't hurt the engine.
Yes, no problem.
It could be.
10W40 is whats safe for usage on that engine. If youre using the car in the winter it is recommended to use 10W30 as a thinner oil for the colder climate
Yes you can but if you are using a 10W30 oil be sure it is synthetic or buy a straight grade SAE 30 Weight Oil. Why? A standard oil (non synthetic) 10W30 oil has too many VI improvers.. additives that will break down in an application such as a lawnmower and cause the oil to no longer be a 30 weight oil. It will quickly become a 20 Weight SAE oil that will no longer protect the engine. A synthetic 10W30 Small Engine oil does not have any of these VI improvers to break down and cause the oil to lose it's viscosity rating. Basically.. do not use a standard 10W30 Car oil for your lawnmower.
If the recommended oil is SAE30 why would you use SAE 10W30? Some mowers recommend either of these weights but if your recommends 30W then using 10W30 will cause it to use oil.
In an emergency, no. Change the oil ASAP. If it's an emergency.... only if you have to do so. It can hurt it. Diesel oil (15w40) is different from 10w30. There are different additives, different qualities, and the viscosity is also different.
10W30
No it is not. The correct weight oil for your car is SAE 5w30.