How to Fix Milky Oil in an Engine

by Synthetic Oil | Last Updated: May 16, 2023

You take care of your car to extend its life. Yet, no matter how often you change the oil and oil filter or do routine maintenance, there are some issues you will encounter that make you flabbergasted. Take, for instance, engine oil that looks milky or creamy. If you see milky sludge under the oil cap or start to notice a loss of performance, you may know you have a problem but don’t know how to fix it. Good thing you are here.

So without further ado, let’s discuss how to fix milky oil in an engine the right way, as well as some tips for preventing it in the future.

**Note** – A quick hello to anyone reading this, I’m Alastair and this is my site Synthetic oil.me. I started this site to help people with their oil questions, and hopefully what you’re about to read will help answer your questions. This page may include affiliate links to the likes of Amazon, which if you make a purchase I qualify to earn a (typically small) commission. Don’t worry as this won’t cost you anything, the likes of Amazon pay any commissions. Thank you in advance for your support as this helps bring you more (hopefully) helpful content.

What is Milky Engine Oil?

Milky engine oil is when the oil takes on a milky, creamy appearance, which is a result of the oil emulsifying with coolant or moisture.

Is it Bad if Your Engine Oil Looks Milky?

Yes, if the engine oil looks more like a milkshake and less like viscous amber, there is something wrong. Milky engine oil is a sign of a serious problem in a car’s engine. It is an indication of a coolant leak somewhere in the engine, and it can lead to serious damage to the engine if left untreated. 

When the oil mixes with coolant, it loses its lubricating properties and can cause increased friction, heat, and wear on the engine’s components, potentially leading to engine failure. The coolant in the oil can also cause corrosion and damage to the engine bearings and other components.

What Causes Milky Engine Oil?

As mentioned earlier, engine oil becomes milky when it comes into contact with coolant. Usually, the coolant is able to mix with engine oil when there is a leak. Knowing the cause is the first step in learning how to fix the milky oil in the engine. Here are some of the reasons coolant is getting into your engine oil and making it look creamy:

Cracked Engine Block

Is your car experiencing a loss of power, overheating, and white smoke from the exhaust alongside milky engine oil? Then you may have a cracked engine block. When this happens coolant is allowed to leak into the oil passage and mix together, turning the engine oil milky. Cracks can occur due to several reasons, such as overheating, age, or physical damage. They are often time-consuming and expensive to repair.

Blown Head Gasket

The head gasket seals the space between the engine block and the cylinder head, and if it fails, it can allow coolant to leak into the oil passages. Coolant mixed with engine oil can cause the oil to turn milky. The head gasket can blow for many reasons, such as manufacturing defects, age, and overheating. Other symptoms of a blown head gasket can include overheating, loss of power, and white smoke from the exhaust, making it similar to several other issues on this list.

Damaged Cylinder Head

Damage to the cylinder head, such as a crack, can also cause coolant to leak into the oil passages and mix with the oil. This can happen due to several reasons, such as overheating, physical damage, or age. Symptoms of a damaged cylinder head can include loss of power, overheating, and white smoke from the exhaust. If you notice any of these, get your vehicle to a service center as soon as you can.

Worn or Damaged Engine Bearings

Engine bearings are used to support the crankshaft and other rotating parts of the engine. If the bearings are worn or damaged, they can allow coolant to enter the oil passages, where it can mingle with your engine’s lubricant. The result? Milky engine oil. This can happen due to several reasons, such as age, poor maintenance, or physical damage. Additional symptoms of worn or damaged engine bearings can include knocking or tapping noises from the engine.

Faulty Intake Manifold Gasket

Here is one that you may see less often than other causes but is still possible. The intake manifold gasket seals the space between the intake manifold and the engine block. If it fails, it can allow coolant to leak into the oil passages and mix with the oil. This can happen due to several reasons, such as age, overheating, or a manufacturing defect. If your car has a faulty intake manifold gasket, you may also notice rough idling, loss of power, and poor fuel economy.

Here’s a quick video:

Condensation

If a car is only driven for short distances and doesn’t reach operating temperature, condensation can form in the oil and cause it to turn milky. This is more likely to happen in humid environments. Condensation can also occur in the engine due to a faulty PCV (positive crankcase ventilation) valve or a damaged air filter, allowing moisture to enter the engine.

However, this type of milky oil is usually temporary and should disappear after driving the car for a longer period to fully heat up the engine and evaporate the moisture.

Water Pump Failure

The water pump circulates coolant through the engine to regulate its temperature. If the water pump fails, it can cause coolant to leak into the oil passages and mix with the oil, causing it to turn milky. Water pump failures are rarer than a few other reasons, but they are more likely to occur when your vehicle is at higher mileage. Other symptoms of a failed water pump can include overheating and loss of power.

Radiator Failure

Lastly, your engine oil may look milky because of a failing radiator. The radiator is responsible for cooling the engine by circulating coolant through the engine block and radiator. If the radiator fails, it can cause coolant to leak into the oil passages and mix with the oil, resulting in an engine oil milkshake. This can happen due to several reasons, such as physical damage, age, or corrosion. The symptoms of radiator failure can include overheating, coolant leaks, and low coolant levels.

Is it Safe to Drive With Milky Engine Oil?

Absolutely not. Milky engine oil is a symptom of a serious issue, usually one that affects not only the performance but the safety of your vehicle. Coolant in the oil can also cause a loss of lubrication and damage engine bearings, which can lead to expensive repairs or even the need for a complete engine replacement.

If you notice milky engine oil, the only place you should go is to the mechanic. Otherwise, you should have your vehicle towed. Ignoring this issue and continuing on will cause the problem to grow more severe. When that happens, your repairs are going to cost infinitely more. Worse, you may permanently damage the engine.

How to Remove or Correct Milky Engine Oil

Correcting milky engine oil depends on the underlying cause of the problem. In some cases, such as if the milky oil is caused by condensation or a minor coolant leak, simply changing the oil and fixing the source of the problem may be sufficient to correct the issue. Otherwise, head to a mechanic to resolve the major issue.

If you wish to simply remove the milky stuff from your engine oil, the process is relatively easy. Here is how:

1. Drain the Engine Oil

The first step is to remove the old milky oil from your car. Drain the oil reservoir completely, following the same steps when changing the oil.

2. Remove Your Oil Filter

Often, the milky oil will get into the oil filter and cling to it. Therefore, it is best to remove the oil filter and replace it with a new one.

3. Replace the Oil

Replace the drain pan plug and get ready to pour in more oil.

4. Run Your Engine

Once you have replaced the oil, start your vehicle. Let it run for 10-20 minutes.

5. Drain the Oil a Second Time

Turn off the engine. Wait for the engine and oil to cool for about 10 minutes. Now, drain this oil. Proceed with changing the oil and oil filter a second time. This is to remove all the remaining milky oil.

6. Ready to Go

With this second batch of fresh oil, the milky oil should be removed entirely. Your car should be safe to drive—unless other problems need to be resolved first.

How to Prevent Milky Engine Oil

Now that you know how to fix milky oil in an engine, let’s briefly discuss how to keep it from ever happening. Here are some things you can do to help prevent milky engine oil:

• Maintain your engine cooling system: Make sure your engine’s cooling system is in good condition, and replace the coolant as recommended by the manufacturer. This will help prevent overheating and reduce the risk of coolant leaks.
• Use the right oil: Make sure you’re using the recommended type and viscosity of oil for your engine, as specified in your owner’s manual. Using the wrong oil can lead to problems such as increased engine wear and overheating, which can contribute to milky engine oil.
• Regularly change your oil: Regular oil changes are important to keep your engine running smoothly and to help prevent problems like milky engine oil. Follow the recommended oil change schedule for your vehicle and use high-quality oil and oil filters.
• Keep an eye on your engine: Monitor your engine’s performance and look for signs of trouble, such as overheating or coolant leaks. Catching problems early can help prevent more serious issues down the line.
• Avoid short trips: Short trips can prevent the engine from reaching operating temperature, which can lead to condensation in the engine oil. Combine multiple short trips into one longer trip to help keep the engine running at optimal temperature.

Final Thoughts on Milky Engine Oil

Milky engine oil is something you never want to encounter, as it telegraphs a serious problem. Yet, learning the signs and how to fix milky oil in an engine can help you should you ever spot it. Keep the signs and causes in mind. Whether you opt to diagnose and repair the problems yourself or have to take your vehicle to a mechanic, you at least know why your engine oil is milky.