1. Improper Installation of the Oil Pan Gasket: If the oil pan gasket was not installed correctly or if the gasket is damaged, it can cause a leak, especially under high pressure created during high-rpm runs. Ensure the oil pan gasket is correctly seated and free from any damage or tears.
2. Excessive Crankcase Pressure: High crankcase pressure can cause oil to leak through various seals and gaskets. Reasons for excessive crankcase pressure include blocked PCV (positive crankcase ventilation) valve or hose, worn or damaged piston rings, or excessive blow-by. Check these components and ensure they are functioning properly.
3. Faulty Front Main Seal: The front main seal is responsible for sealing the gap between the crankshaft and the engine block at the front of the engine. If this seal is damaged or worn, it can cause a leak when the engine is running at high rpms due to increased oil pressure. Replace the front main seal if necessary.
4. Improperly Sealed Oil Filter: Ensure that the oil filter is properly tightened and seated according to the manufacturer's specifications. A loose or improperly installed oil filter can cause oil leaks.
5. Damaged or Cracked Oil Pan: Check the oil pan for any damage, cracks, or deformation that may have occurred during the rebuilding process. If the oil pan is damaged, it can cause oil to leak under high pressure.
6. Issues with the Distributor: Sometimes, leaks around the front of the engine can be traced to issues with the distributor. Problems with the distributor O-ring or its cap gasket can cause oil to leak from the front of the engine. Check these components for any signs of damage or wear and replace them if needed.
7. Incorrect Oil Level: If the engine is overfilled with oil, it can cause excessive oil pressure and result in leaks. Check the oil level and ensure it is within the specified range.
8. Oil Pressure Issues: If the oil pressure is too high due to a faulty oil pressure regulator or a clogged oil filter, it can lead to leaks. Verify the oil pressure and address any issues if the pressure is out of the normal range.
I recommend thoroughly inspecting the engine from the front, paying close attention to the areas mentioned above, to identify the exact source of the leak. Once the cause has been identified, you can take appropriate measures to fix it and prevent further oil leaks.
