Engine oil sludge may signal a serious problem with your engine and an expensive repair bill in the future. Even so, it’s a problem that can be solved. If detected early on, it may not even have any long-term consequences for your vehicle. As with all other car components, maintenance is key. Inspecting your oil level and oil quality on a regular basis could save your engine. Whether you are just wondering what causes oil sludge, or you are actually facing this issue and want to fix it, you’re in the right place. Let’s talk oil sludge!

What Is Oil Sludge?

Engine oil sludge develops when the oil starts to break down. Once it succumbs to shearing forces and other factors inside the engine, the oil thickens up, begins to solidify, and collects on the engine walls. 

Thicker oil can no longer lubricate the engine, increasing metal-on-metal friction, which ultimately speeds up wear of the internal components. This means you’re running a risk of overheating the engine or destroying the internals. In the end, this will eventually lead to an expensive repair.

Oil Sludge Causes

Finding out the cause of engine oil sludge is not entirely straightforward. The reasons for it can be numerous, including using poor quality oil, ignoring oil service intervals, coolant contamination, moisture contamination, or even idling the engine for prolonged time periods frequently.

It needs to be understood that the sludge does not suddenly appear out of the blue. Instead, it slowly builds up over time. However, bad driving habits can speed up this process. This includes, said idling, or using the car to only cover short distances. The other extreme is also harmful and amplifies the chances of engine oil sludge forming — pushing the engine to the limits and keeping the oil at extremely high temperatures for extended periods of time.

Another but not as common cause is oil contamination by unburned fuel. This is more common in diesel engines than gasoline ones although it’s not unheard of in gasoline engines. 

How to Detect Engine Oil Sludge?

To identify it, you can simply pop the hood, remove the oil cap and take a quick look. In many cases, you will see the oil sludge formed on the cap. It’s also worth peeking inside the engine. You can either remove the valve cover and inspect the valve train for signs of oil sludge, or you can remove the oil pan and see what’s going on around the crank. The former is much easier to do, and will give you all the information you need as far as the extent of the problem and how serious it is. 

Depending on what you drive, your ECU can detect issues with oil pressure, which is indicative of oil sludge in addition to a few other problems. You might see a check engine light or an oil pressure/temperature warning light. In any case, if you find that sludge has formed in your engine, you should immediately take steps to rectify this issue.

How to Remove Engine Oil Sludge?

So, what should you do if you find oil sludge in your engine? There is a way for you to solve this problem at home. However, it’s important to note that success is not guaranteed. Whether you’ll fix this issue using the method we’re about to discuss depend on how much sludge there is and how long it’s been sitting there. 

Flushing the Engine with a Sludge Remover

The first thing to do, if you find oil sludge in your engine is to use an engine sludge remover. These are available at most car parts stores and are easy to use. They typically come in cans of roughly 10 ounces and are directly poured into the engine. 

Simply remove the oil cap and pour the sludge remover. To utilize the maximum cleaning effect, you should then drive the car for about 100 miles but avoid putting excessive load on the engine. It’s important to mention that this part of the process varies for each product and some instructions may recommend simply letting the engine idle for 5-10 minutes. Read the instructions provided with your sludge remover of choice.

After that, you need to drain and replace the motor oil, as well as the oil filter. In cases where the engine is severely contaminated, you may try to repeat this process 2-3 times.

If this doesn’t solve your problem, you’ll have to manually clean the engine, which is a whole different beast. This implies taking the engine apart to a certain extent, depending on the severity of the oil sludge condition. 

How to Prevent Oil Sludge?

If you have gone through the cumbersome process of removing oil sludge from your engine, you will likely want to avoid having to do it again in the future. The most important thing you can do to prevent oil sludge is to change your oil and oil filters regularly.

After surpassing the usual recommended 10,000 miles or 1 year (depending on the make and model), the oil slowly starts to lose its properties, and no longer offers lubrication. Keeping up with the maintenance of your vehicle is the number one way to prevent oil sludge from forming.

However, oil quality also plays a role in this matter. You should carefully select the oil you use. It should be of high quality and meet the requirements set by the manufacturer. Brands such as Motul offer some of the most advanced fully synthetic oils that feature things like EsterCORE technology, improved additive packages, and more! These types of engine oils are far more durable than your standard semi synthetic or mineral oil. 

If you want to be sure that nothing will happen to your engine in terms of sludge, Motul and similar brands are the way to go. Check our selection of Motul oils and find one that matches your engine. Saving a few dollars by using cheap motor oil is simply not worth it — replacing the engine oil is one of the simplest and cheapest service procedures to perform but it is crucial for keeping your car reliable for years to come.

You should also think about how you use your car. Sludge is more likely to develop in cars that are often used on short trips. In general, engines suffer when being constantly used for short journeys, without having time to warm up. If you can, try to take your car for a longer drive at least once a week, so that your engine can “recover.”

Engine Oil Sludge Is a Serious Issue but Can Be Fixed

Engine oil sludge could be summarized as a common and costly issue. You certainly want to avoid it and to do so, you should make sure to change your engine oil at set intervals (usually every 10-15 thousand miles or 1 year, whichever comes first) and also check the oil level and condition from time to time. 

As a means of prevention, changing the oil should also be one of the first things you do after buying a used car. It is better to be cautious and change the oil sooner, rather than to face expensive repairs or even an entirely destroyed engine later. Check our selection of quality engine oils and find one that will keep your car sludge-free for years to come!