If your engine longevity is a concern to you and you want to keep your engine running nice and smooth, you must do regular check-ups and maintenance. The most important thing for engine longevity is having an appropriate circulation of quality engine oil.
Engine oil is the lifeblood of every engine; it cleans and lubricates the internal engine parts and makes its movement friction-free, but that’s not all.
This is just a tip of what it does. Motor oil helps to maintain an engine’s optimum operating temperature, preventing the engine from overheating.
If you don’t want to encounter engine oil clumpy issues, you need to carry out a regular oil change. Failure to do this, your engine oil might clump and stick together and clog your engine in the process. This is known as engine sludge.
Those who don’t learn the symptoms and how to clean engine sludge are putting their cars at risk, which could cause severe engine damage resulting in costly repair bills.
What is engine sludge?
Sludge is oxidized oil that turns into a gelatinous material
Your engine oil is normally a closed system. The oil goes through the engine to lubricate it, passes through a filter to remove any debris and then cycles back through the pump and engine again.
If there’s a leak anywhere where air can get in, that oil oxidizes. That creates a chain reaction that produces sludge—a thick, Jello-like substance that won’t flow freely the way oil should.
- Sludge is a major problem for two reasons. First, sludge is super thick so it can block up valves and restrict oil flow. Second, sludge only develops if you have a leak somewhere to let air into the oil lines, so you’ve definitely got a leak to fix somewhere.
- So what causes engine sludge? Sludge only occurs when you have an oil leak or very old engine oil that has been exposed to the air for a prolonged period of time (i.e. the car was sitting on cinderblocks with the oil cap off).
What Does Engine Sludge Do to Your Car?
Motor oil is the lifeblood of your car and engine. A failure to properly maintain the quality and condition of the oil will lead to disastrous results. Engine sludge can block up key parts of the engine, preventing good oil from getting through.
When engine sludge is left unattended, it will result in total engine failure sooner or later. At that point, your engine would need to be reconditioned by a professional, which would be both expensive and time-consuming to do.
What are the Causes of Engine Oil Sludge?
To tackle engine oil sludge effectively, it’s crucial to identify its root causes. Sludge develops when oil breaks down and becomes contaminated with dirt, debris, and other impurities.
Let’s explore these causes in detail and understand why each one can lead to the formation of engine oil sludge.
| Causes | Description |
| Not changing engine oil | Neglecting regular oil changes can lead to sludge buildup. |
| Low-quality oil | Choosing inferior oil products can accelerate sludge formation. |
| Faulty PCV valve | A malfunctioning PCV valve can increase the risk of sludge. |
| Short Commutes | Brief trips without optimal engine temperature promote sludge. |
#1. Not Changing Engine Oil.
One of the primary culprits behind engine oil sludge is neglecting to change your engine oil regularly. This simple maintenance task is often overlooked, but its consequences can be severe.
| Vehicle Type | Recommended Oil Change Interval |
| Passenger Cars | Every 3,000 to 5,000 miles |
| Trucks and SUVs | Every 5,000 to 7,500 miles |
| High-Performance Cars | Every 3,000 miles |
And you must know that:
- Infrequent oil changes or exceeding recommended mileage intervals can lead to sludge formation.
- Regular oil changes are essential to prevent sludge buildup.
#2. Using Low-Quality Oil Brands.
Choosing budget-friendly, inferior oil products may seem like a cost-effective choice initially, but it can have dire consequences for your engine.
| Oil Type | Quality Level | Features and Benefits |
| Synthetic Oil | High-quality | Offers excellent engine protection and extended service intervals. |
| Conventional Oil | Standard | Suitable for regular use but may require more frequent changes. |
| Blended Oil | Mid-range | A compromise between synthetic and conventional oils. |
And it’s better to know that:
- Poor-quality oils lack the detergents and additives needed to prevent sludge formation.
- Investing in high-quality oil can significantly reduce the risk of engine oil sludge.
Low-quality Oil: A Risky Choice for Your Engine
When it comes to engine oil, not all products are created equal. Low-quality oil can be a significant contributor to engine oil sludge, and understanding why is crucial. Let’s check and find problems.
Poor Oil Additives
In the world of engine oil, additives play a critical role in maintaining engine health. These additives include detergents and dispersants, which prevent the accumulation of sludge and deposits in the engine.
| Additive Type | Function | Effects on Engine |
| Detergents | Clean and remove deposits from engine parts | Prevent sludge and varnish formation. |
| Dispersants | Suspend contaminants in oil, preventing buildup | Keep engine components clean. |
| Anti-wear agents | Reduce friction and wear on engine parts | Enhance engine longevity. |
| Anti-oxidants | Prevent oil breakdown and oxidation | Extend oil life and maintain viscosity. |
#3. Faulty PCV Valve: A Silent Culprit.
The Positive Crankcase Ventilation (PCV) valve might not be a household name, but its malfunction can lead to engine oil sludge.
PCV Valve Function
Understanding the role of the Positive Crankcase Ventilation (PCV) valve is essential in grasping how it contributes to sludge formation.
| PCV Valve Status | Function | Consequences of Failure |
| Functional | Vents excess gases and moisture from the crankcase | Prevents sludge and deposit formation. |
| Malfunctioning | Fails to ventilate crankcase effectively | Traps contaminants, leading to sludge. |
| Stuck Open | Allows unfiltered air into the intake manifold | Increases the risk of oil contamination. |
#4. Short Commutes: A Tricky Situation.
Short commutes may seem harmless, but they can inadvertently promote engine oil sludge formation.
Impact of Short Drives
Explaining how brief trips can contribute to sludge buildup is vital in helping vehicle owners recognize this often-overlooked issue.
| Driving Habits | Effects on Engine | Strategies for Prevention |
| Short Commutes | Engine doesn’t reach optimal operating temperature | Combine short trips when possible. |
| Stop-and-go | Increased condensation and fuel contamination | Schedule regular maintenance check-ups. |
| Cold Weather | Slower warm-up times, promoting sludge formation | Consider synthetic oil for faster warm-up. |
Symptoms of Engine Sludge
Carry a regular oil check to avoid clumps. Look through your engine to identify the accumulation of sludge by removing the valve cover.
Failing to do so will clump the engine oil and clog the entire working system of the car’s engine. Go through the symptoms of and process on how to clean engine sludge to evade expensive engine repairs.
- Poor engine performance: Sludge restricts the oil flow and naturally leads to reduced lubrication and increased friction, resulting in poor engine performance.
- Overheating: Engine sludge buildup can interfere with the cooling system. This causes the car’s engine to overheat.
- Reduced fuel efficiency: Sludge can also have a negative effect on the fuel-air mixture and combustion process, resulting in decreased fuel efficiency.
- Oil pressure warning light: Sludge buildup can obstruct the oil passages, which triggers the oil pressure warning light on the dashboard.
- Knocking or tapping noises: Insufficient lubrication because of engine sludge can cause metallic components to rub against each other, producing knocking or tapping noises and ultimately causing wear.
How to Clean Engine Oil Sludge
Getting oil out of your car is something you shouldn’t take lightly. So, I’ll share a technique so you could be able to continue to keep on top of getting and keeping sludge out of your engine. Grits in engine oil give you low oil pressure and tear down your engine.
This technique is effortless to follow and will cost less than twelve bucks. This will provide you with a crystal-clear picture of cleaning engine sludge with diesel. So, instead of purchasing an engine flush for this, you only need a few liters of diesel.
Things Needed:
- Oil catch pan
- Socket wrench
- Ratchet handle
- Diesel
- Funnel
- Oil filter wrench
- Quality engine oil
- Oil filter
- Mechanic layboard
Before we dive into the steps, if the sludge in your engine is not much or you are just concerned about your engine longevity, you don’t have to follow the below steps.
All you have to do is purchase Liqui Moly 2037, add it to your engine oil, start the car, and run it on idle for 5 minutes. Then shut off the engine and do your regular oil change. It’s that simple. If not, stick to the steps below.
Step 1. Park your car on a flat ground
When working under your car, one of the things you have to do is to park your vehicle on hard, level ground.
Then, block off the rear wheels, so the car doesn’t move when you slide under. If you’re working in a garage, the garage pit will be the best place to carry out this flush.
Step 2. Jack up your car
After parking your car in a safe place, you have to jack it using a floor jack or hydraulic jack so you can easily slide under the car and carry out your work easily.
Step 3. Drain out the old oil
Grab your garage layboard and slide it under your vehicle. Place your oil catch pan directly under the engine sump. Take the right socket wrench and ratchet handle to lose the sump so the old oil will drain into the catch pan.
After draining all the old oil, guide the sump by hand and snug it with your wrench. Remember to pour the old oil into a container and dispose of it later.
Step 4. Fill the engine with diesel or kerosene instead of motor oil
This is a critical step that you have to take. Ensure you pay close attention to this. Fill your engine with a mixture of diesel and engine oil.
If your vehicle uses 5 liters of motor oil, you have to pour 4liters of diesel and a liter of motor oil. This is the best homemade engine flush, and it works effectively as an engine flush could.
Step 5. Start the engine and allow it to run
Next, start the engine and allow it to run at idle. Let it run for 5-10 minutes. Do not drive the car, do not engage the gears, and do not rev the engine as this can result in engine tear down between moving components. I recommend applying this step to older vehicles.
What if I’m using a newer car? You still have to utilize a mixture of diesel and motor oil, but you won’t have to start the vehicle after pouring the homemade flush, head over to your fuse box and remove the fuel pump relay, so it will not supply gas to the engine.
There is more than one relay in the fuse box that looks like. You might need to visit your owner’s booklet to locate the fuel pump relay.
Try turning the ignition key to make sure the car doesn’t start. Now, crank the engine several times. You can do this up to 50-100 times. The reason for this is to prevent the engine from starting so it won’t cause damage to internal engine components.
Mere cranking the engine will enable the oil pump to circulate the diesel around the engine and wash off the grits in it.
Step 6. Drain out the homemade flush
Take your oil catch pan and slide it under the vehicle. Place the catch pan directly under the sump so you won’t mess up the area.
Unbolt the sump and allow the homemade flush to drain into the catch pan using the right tool you used earlier. Once the diesel is out, snug the sump by hand and torque down with a socket wrench.
Step 7. Replace the oil filter
The old oil filter had to be in place while performing the previous steps. Now, you have to take it off by loosening it with an oil filter wrench.
Grab your new oil filter, feed it with quality engine oil until it’s half-filled and snug it by hand. Do not use an oil filter wrench while tightening it, but you have to make sure it’s well tightened by hand.
Step 8. Pour new quality motor oil into the engine![]()
Get a recommended oil and pour in the engine, start the engine and let it run for 30 seconds, then turn it off and gauge the oil level.
Make sure the oil is gauged. Add Liqui Moly (20002). I usually add this product to my engine during every oil change. So, I recommend adding this product to your engine oil after a successful engine flush.
Liqui Moly (20002) is a high-tech ceramic wear protection product; thus, it reduces friction and prevents metal-to-metal contact, which makes it the best product to use after flushing your engine. Watch this YouTube video for a visual presentation.
Preventing Engine Sludge
#1. Get regular oil changes.
Over time, your oil picks up all kinds of microscopic debris and junk. The heat and churn from your engine also break the oil down.
If you don’t change the oil out when that happens, the odds you spur a leak and develop sludge increase. Get your oil changed every 5,000 miles (8,000 km) or once a year—whatever happens first.
- If your vehicle is more than 20 years old or so, get an oil change every 3,000 miles (4,800 km) or so.
#2. Replace your oil filter yearly.
At least once a year, ask your mechanic to swap out your filter when you’re getting the oil changed.
The oil filter is responsible for absorbing all of the gunk in the oil as it cycles through the engine. But if the filter never gets changed, it can create a pressure imbalance in the oil lines, which can create leaks that let air in.
- There’s a lot of debate about how often you need to get your filter changed, but doing it at least once year should be more than enough.
#3. Switch to a synthetic oil.
Refer to your manual and look at the cap on your engine oil reservoir to determine if your engine can handle synthetic oil.
If it can and you’ve been using conventional oil, make the change to the synthetic stuff. Synthetic oil is better for your engine and less likely to convert into sludge if it’s exposed to air.
- Synthetic oil typically has a lower viscosity, which means it flows more easily than the conventional stuff.
#4. Walk or bike instead of driving short distances.
If you have to go 5 miles (8.0 km) or less, don’t drive unless you have to. These short trips are especially bad for the health of your engine because the oil doesn’t really have time to “warm up” and remove debris in your oil lines.
Also, you spark combustion every time you start the vehicle, so starting and shutting the engine off frequently puts unnecessary wear and tear on your engine.
- This is even more problematic if you’re making these short trips in very hot or cold weather. Extreme temperatures make short trips even harder for engines.
#5. Shut your engine off if you’re idling for long periods of time.
Letting your engine run idly without actually driving cycles the oil through your vehicle. But since the pistons aren’t firing at more than a slow clip, the oil never gets as hot as it’s designed to. This leads to a lot of residue inside of your oil lines as none of it burns away.
- It’s okay to idle if you’re going to get out of the car and hop back in or if it’s especially cold out while you’re waiting for someone, but it’s better to shut the engine off and turn it back on if you’re waiting more than 30 seconds or so.
Why Is It Important to Clean Engine Oil Sludge?
Now that you know what engine oil sludge is, you might be wondering why it’s so important to get rid of it. After all, it’s just a messy substance – what’s the big deal?
Well, the truth is that engine oil sludge can actually be very harmful to your car. If left untreated, it can clog up your engine and prevent oil from flowing properly.
This can lead to all sorts of problems, including decreased performance, increased fuel consumption, and even engine failure.
In short, it’s important to clean engine oil sludge because it can save you a lot of money in the long run. Not to mention, it’ll keep your car running smoothly and efficiently!
Cost Considerations
The cost of cleaning engine sludge can vary significantly depending on the severity and method used.
- A simple engine flush may cost between $50 and $150.
- More extensive mechanical cleaning by a professional mechanic can range from $500 to over $1,000 for severe cases requiring disassembly.
It’s important to weigh the cost of cleaning against the potential consequences of ignoring the issue.
Severe sludge buildup can lead to costly engine damage or even complete engine failure if left unchecked. In many cases, the cost of cleaning is a worthwhile investment to protect your vehicle and avoid more expensive repairs down the line.
FAQs.
Q: Can you remove sludge out of an engine?
Yes. Taking out sludge from your engine is something you shouldn’t take for granted. Ensure you flush your engine during oil change whenever you notice particles in your oil or sludge in the head cylinder.
Q: What is the best engine sludge remover?
Aside from the homemade engine sludge remover (a mixture of diesel and oil or kerosene and motor oil), the best engine sludge remover is Liqui Moly 2037, a highly effective detergent additive that cleans the interior engine before the flush. It is an overall sludge remover to flush your engine thoroughly and extends its longevity.
Q: How bad is engine sludge?
Is engine sludge bad? Engine oil sludge can cause catastrophic engine damage if overlooked for a very long time.
When the engine oil clump together to form engine sludge, the oil pump will not properly circulate oil throughout the entire engine system to lubricate the moving parts.
Suppose this happens; it will cause frictions and metal-to-metal contact resulting in expensive repair costs.
Q: Will synthetic oil clean sludge?
All modern motor oil has a percentage of solvent that will, to a lesser or greater extent, clean engine sludge, and some clean it better than others.
That said, synthetic oil removes engine sludge to an extent. This doesn’t mean you won’t flush your engine when you notice oil sludge in your vehicle engine.
Q: Can frequent oil changes remove sludge?
A frequent or regular oil Change is a preventive measure to keep your engine far from sludge. However, if you have engine sludge already, the best option is to flush the engine and keep up with regular oil changes.
Final word
It’s no coincidence that one of the most overlooked engine problems can lead to expensive repair costs.
For your car to run nice and smooth, several engine components have to work together, and if anything goes wrong, the whole system will be affected. Watching out and preventing engine sludge is a decision you won’t regret.
Watching out for engine oil sludge symptoms, doing a regular oil change, reading your service manual, and knowing how to clean engine sludge will help your engine run smoothly for a long time. Little preventive measures will save you from many engine problems in the future.