Engage in Engine Health: Troubleshooting Engine Knocking When Overfilled with Oil

Recently, many car owners have found themselves in a peculiar situation where they unexpectedly heard a slight knocking sound from their engine after filling it with a little more than the recommended half liter of engine oil. This article aims to address the root causes of such engine knocking and offer practical solutions to ensure your engine operates smoothly.

The Causes of Engine Knocking Post-Overfilling

Overfilling your engine with an extra half liter of oil can lead to several issues that may explain the knocking sound you are experiencing. Here are some possibilities:

Overfilled Oil

Excess oil can lead to foaming as the crankshaft splashes through the oil. This reduced lubrication can cause a knocking sound and increase pressure in the crankcase. The excess oil can also affect the engine's overall efficiency and performance.

Hydraulic Lifter Malfunction

Your engine uses hydraulic lifters, and if they malfunction due to overfilling, you might hear a knocking or ticking sound. These lifters rely on a film of oil to function correctly. When filled to excess, the film is disrupted, leading to noise and potential damage.

Oil Aeration

Excess oil can cause aeration, where air gets mixed with the oil. This aeration can decrease the oil's ability to lubricate properly, potentially leading to knocking sounds from overheated components.

Oil Pressure Issues

Overfilling can result in increased oil pressure, which may affect the engine's oil pump and cause knocking. High oil pressure can place unnecessary strain on the engine, leading to premature wear and tear.

Preventive Measures and Recommendations

While the initial overfilling incident may seem like a minor inconvenience, improper management can lead to significant engine damage. Therefore, it is crucial to take immediate action:

Check Oil Level

Use the dipstick to check the oil level. If it is above the maximum mark, you should drain the excess oil to avoid further issues. Excess oil can cause overpressure, leading to premature wear of components and a higher likelihood of knocking sounds.

Monitor the Sound

If the knocking persists after correcting the oil level, it's advisable to have the engine checked by a mechanic. Early detection can prevent potential damage and expensive repairs.

Avoid Driving

If the knocking is severe, avoid driving the vehicle until the issue is resolved to prevent further damage. Continued operation can exacerbate the problem and require more extensive repairs.

Avoiding Low Oil Issues

Low oil levels can also cause engine knocking. If you allowed the oil to drop significantly and then topped it up, especially after finding the engine had been standing with low oil, the film on the crankshaft and camshaft may have thinned out, leaving no protection for the bearings and cam lifters. In such cases, you should have changed or topped up the oil and turned the engine over until you had oil pressure. Turn the engine over to help distribute the oil and lubricate the critical components.

It is crucial to monitor your oil levels regularly and never let them drop below the minimum mark. Regular oil changes and top-ups are essential for maintaining engine health and preventing knocking sounds and potential damage.

For intrepid DIY mechanics or those seeking immediate peace of mind, consulting a professional mechanic is recommended. They can provide a thorough inspection and help you avoid potential engine damage and costly repairs.