Final answer:
Oil pressures typically indicate a higher value during start, peak beyond normal levels, and are displayed in psi or kPa. This is especially true when the oil is cold as it has a higher viscosity, requiring more pressure for circulation.
Step-by-step explanation:
Oil pressures should show a higher value during start and may peak beyond normal operational values, and are displayed as psi (pounds per square inch) or kPa (kilopascals). This is due to the fact that oil's viscosity is higher when cold; therefore, more pressure is required to pump the oil through the engine. In the context of a hydraulic press, when a 250-liter volume of oil is subjected to a 2300-psi pressure increase, one can calculate the bulk strain and the absolute decrease in volume, considering the compressibility of the oil. The impacts of pressure on the fluid's physical properties such as strain and volume change are crucial in the application of these principles in practical scenarios, like oil gushing and hydraulic presses.