For an aircooled VW Beetle, use Castrol GTX2. It has the right viscosity.
In my beetle I run SAE30 oil in winter, SAE40 in summer. I change oild religiously at 3K minle intervals without fail. Aircooleds don't seem to like multi-viscosity oils. If it's below freezing out the SAE20W oil is called for.
5-30 in the summer is recommended. If you have the money I would run a Lucus oil stabilizer.
most mowers run fine on 10W-30 automotive motor oil.
a motor can not run with out oil, the motor will seize up and can break parts
.Mixing a small amount of oil in the diesel fuel will not hurt a motor. The motor will run rough and produce black smoke.
Motor oil is used to run cars. Cars add pollutants to the air when they are running. This is how motor oil can be harmful to the environment. It can also kill plants and animals if not gotten rid of properly.
When you run your car low on oil you increase the instance of burning your motor. If your motor burned out your car won't work.
Most motorcyles have a liguid clutch which means they run in motor oil so when you change your motor oil you are changing your (gearbox) transmission oil and to check your (gearbox) transmission oil level you check the motor oil level.
If you put in to much oil it will smoke really bad, or will not run. If not enough oil you will damage motor.
Motor oils come in different grades. The higher the grade, the better quality the motor oil. Some high end vehicles require better quality motor oil to run at their utmost. Otherwise, any grade will do.
How much? The good news is you'll run quieter.
Need more info. What kind of car? What model? What year? How many miles? Most cars will run with no oil in the motor, Only for A short time, This will ALWAYS ruin motor, Oil level being full does not make the car have oil pressure, although the car will not have oil pressure without oil in the motor. Going by the info. given, The motor needs rebuilt, This may not be the case though. could simply have a bad sending unit or guage.