20-40 lbs
normal oil pressure is 48 to 60
The oil gets thinner. It is normal for the oil pressure to drop after the engine has reached full operating temperature. If you have from 30-40 psi pressure when the engine is hot then that is normal.
It will vary, depending on engine load, but at idle it should be around 30-35PSI. On a light to moderate throttle, it will dip slightly to 25-30 PSI.
The normal oil pressure on a GM 305 engine is between 40 and 60 PSI depending on the model year. High oil pressure is needed to allow for proper circulation through the engine.
Need to know the year.
80 lbs
It is normal for the oil pressure to drop when the engine is warmed up and at an idle.
Around 40
Oil pressure has to built up. As long as the pressure is normal and the oil level is good. There is no problem.
A good rule of thumb is to look for 10 pounds of oil pressure (or more) per 1000 RPM of engine speed. Below that, the engine may not get proper lubrication.
No. The atmospheric pressure is too low. Perhaps an internal combustion engine could be designed to operate on Mars, but it would not be 'normal.'
Oil pressure gauges are notoriously inacurate. Pressure should be high when the engine is cold, or the accelerator is pressed hard. It's also possible the sensor is damaged.