What component should be checked for excess oil to return to the oil pan?

The pressure relief valve is a crucial component that regulates oil pressure in an engine. When the oil pressure exceeds a certain level, which can happen when the oil is hot or if the oil is too thick, the pressure relief valve opens to allow excess oil to bypass the system and return to the oil pan. This action prevents damage to the oil pump and other components due to excessive pressure. A malfunctioning pressure relief valve may not open when needed, leading to higher oil pressure and potential engine damage.

In a typical engine scenario, if there is an issue with oil returning to the pan, checking the pressure relief valve is essential as it directly impacts the oil circulation system. If it fails to function properly, it could create a backup of oil and prevent proper lubrication of engine parts.

The other components do play significant roles in the oil system but do not directly serve the function of regulating excess oil back to the oil pan in the same manner as the pressure relief valve.