Cough cough cough – is your engine’s throat sore?

My young son made a great comparison the other day to why you shouldn’t let your engine oil level go low. He explained if it gets dry it’s like when your throat gets sore and that’s why it starts coughing (knocking).

One common symptom of low oil levels is engine knocking, also known as detonation or pinging. This is a metallic sound that occurs when the air/fuel mixture in the engine detonates prematurely, causing a knocking or pinging noise. This can be caused by a variety of factors, such as low oil levels, high engine temperatures, wrong fuel use, or a malfunctioning ignition system.

Normally you may think of knocking as related to fuel mix condition, so let me explain how oil level can also lead to this problem. Low oil level can cause engine knocking because it can result in insufficient lubrication of the moving parts in the engine. When the oil level is low, the oil pump may not be able to distribute oil to all the necessary parts of the engine, leading to metal-to-metal contact between components. This can cause excessive wear and tear on the engine’s parts. In this case the piston and rings wearing are of importance as it can then cause poor sealing. This is not just from the mechanical sealing from rings, but also from the very final sealing produced by the lubricant, with both leading to incomplete compression and combustion at the wrong stage of the cycle leading to a less smooth reciprocal motion, often heard as knocking or ticking noise.

Additionally, low oil pressure from can also be caused by low oil level, which as flow is related to pressure can cause the oil filter to become clogged much earlier (due to lack of pressure) and not able to provide proper lubrication to the engine.

Often people think a knock is an early symptom something is wrong. However, if you can hear a knock that means the wear is often well under way, and it can often be detected much earlier there is an issue with a combination of regular oil level, topup and lab analysis monitoring of the oil. After all, in my sons cough analogy a cough means you are already ill, but wouldn’t it be better to detect the problem right at the moment it starts with wear metal analysis.

It is important to detect these wear particles early and identify if they are normal rubbing wear as occurs in all systems or abnormal large particles. In this case when the oil level is low, the engine is not properly lubricated, which can lead to increased friction and wear on the moving parts, specifically sliding wear. This can cause serious damage to the engine if not addressed in a timely manner. You will often see no visible signs of wear until the very final stages before a failure. For example I did some research with a vehicle OEM on bearing wear and we were able to detect abnormal bearing wear from the copper, lead and tin values often 1 to 2 maintenance services before it was visible on the bearing shells and even longer before the final failure. As with any ailment – human or mechanical, detecting the problem is early is the best chance of a good outcome. So it’s important to check what is wearing from your oil analysis which can detect problems potentially months or years in advance of the final catastrophic failure.

Sliding wear occurs when two surfaces in contact move relative to each other and overcome boundary Lubrication (the toughened layer produced by anti-wear additives in your oil), causing the removal of material from one or both surfaces. Lack of lubrication from low oil levels can greatly increase the chance of sliding wear, as the surfaces are not protected by a lubricant film and are more likely to come into direct contact with each other. Sliding wear is large in nature and shows striations or large scratches in the direction of wear. You can read more about sliding wear in this article.

What is sliding wear?
Sliding wear from diesel engine with low oil level. Notice the long horizontal lines called Striations which are the best sign of this type of wear.

Oil analysis is an important tool for detecting these symptoms and potential issues. By analysing the oil from your engine, the lab can determine the presence of metal particles, which can indicate increased wear and tear on the engine. They can also test for the presence of contaminants such as water or fuel, which can indicate issues such as leaks or a malfunctioning fuel system.

By regularly monitoring your engine oil through oil analysis, you can quickly detect potential issues and take action before they become major problems. This can help to prolong the life of your engine, reduce downtime and unexpected repairs, and keep your equipment running at peak performance.

In conclusion, keeping a close eye on your engine oil level is crucial for maintaining the health of your vehicle or machinery. Regular oil analysis can compliment this by detecting potential issues before they become major problems, and help you to keep your equipment running at peak performance. As my son explained, it’s just like taking care of your body, if you don’t take care of it, it will start to feel poorly and start coughing.