Oil in Coolant [Causes and Solutions to Coolant in Oil] 

Finding oil in coolant sends many people into instant panic. If you act immediately, you can spare yourself from a headache. Meanwhile, if you do not attend to the issue as soon as possible, it can result in costly repairs and irreversible damages. 

Oil in the coolant is dangerous. Not to mention, it is costly as it can damage the most critical parts of the engine. The most common culprits are problems in the head gasket, air cooler, transmission cooler, and engine block. Meanwhile, the best solutions include replacing the problematic components and keeping the engine clean. 

Read on to learn more about oil in coolants. More importantly, we’ll also talk about the causes and solutions to coolant in the oil. You don’t have to be a pro to understand the problem and execute the necessary solution. 

Causes of Oil in Coolant 

oil in coolant

There are several culprits when oil mixes with coolant. A quick inspection of the engine is necessary to pinpoint the exact reason:

1. A Damaged Head Gasket 

Head Gasket Prevents the Coolant from Leaking

The engine has two main parts – the cylinder head, where you will find the spark plugs, camshafts, and the cylinder block, which houses the cylinders and pistons. Between these two parts, you will find the head gasket. The latter seals the firing pressure. More importantly, it prevents the coolant from leaking. 

Compromises the Overall Performance of a Vehicle

A blown or damaged gasket compromises the overall performance of a vehicle. Among others, it can result in white smoke, engine overheating, milky white coloration, bubbling in the radiator, and coolant loss, even when there is no leak. 

Compression Test

Confirming the presence of a blown head gasket is possible with a compression test. Before doing this, take the spark plugs off. If there is a problem, the compressed air will bleed in one of the cylinders during the test. Alternatively, you can also perform a chemical test. 

2. A Malfunctioning Air Cooler 

Cools the Air Before It Enters the Engine

Most gasoline engines will not have an air cooler. Nonetheless, it is a common feature in turbo-charged engines. It cools the air before it enters the engine. This way, the air will have a lower temperature for maximum power during combustion. 

Can Crack in Time

Over time, the air cooler is prone to damage when oil and coolant mix. It can crack, which is also normal as a result of wear. More so, a leak can start once the crack is apparent. The good thing is that replacing the oil cooler is cheap. Do this before the damage gets to the other parts of the engine. When the latter happens, the repair is more expensive. 

3. Leaking Transmission Cooler 

Cool the Transmission Fluid

As the name implies, the main function of a transmission cooler is to cool the transmission fluid. It prevents overheating, especially when the engine is under a lot of strain. The latter often happens when it is too hot or when there is a heavy load. In such instances, the engine needs to exert a lot of effort to work. 

Cracks Between the Cooler and the Radiator

Cracks can be apparent between the cooler and the radiator. As a result, the transmission fluid will mix with the coolant. The same thing will happen with oil. If you do not act immediately, this will damage the transmission beyond repair. Hence, the only option is an expensive replacement. 

4. A Crack in the Engine Block 

Location of Cylinder and Other Vital Vehicle Components

An engine block is where you will find the cylinder and other crucial components in a vehicle. As the engine block works, the pistons in the cylinders will move. As a result, it will turn the crankshaft.

Signs of a Problematic Engine Block

On the other hand, you will notice low engine compression, smoke, and frozen coolant when problematic. More so, another common tell-tale sign of its failure is oil in a coolant reservoir. 

Damaged Engine Block Causes

There are many reasons why the engine block cracks. Among others, it can be because of age. Exposure to extreme heat and dirt accumulation can damage the engine block. At the same time, you can also blame friction. 

5. An Overheated Engine 

Causes of an Overheated Engine

An engine can overheat because of different reasons. For instance, it can be a failing cooling system, causing the temperature to shoot up. You can also blame high temperatures and difficult driving conditions. 

Different things can happen when an engine overheats, and one of the most common is the mixture of oil and coolant. It can lead to oil flow into the coolant, which happens because of a broken head gasket—the latter fuels internal leakage. 

Dangers of Coolant in Oil 

The presence of coolant in engine oil is not one thing that you should ignore. The sooner you notice its presence, the better. Oil and coolant may be both fluids, but they maintain separate functions. Therefore, when they mix, you might end up with a nightmare.

Imminent Engine Failure

Oil and coolant have different chemical properties. A coolant is water-like, while engine oil is thick and viscous. When they mix, they cannot deliver their intended function, and hence, engine failure is imminent. From weird noises to overheating, such a mixture will give birth to different issues that can compromise the performance of your car. 

Again, what are the causes of oil in the coolant? If oil is present in your car’s coolant or vice versa, then you have to check your car’s gaskets or seals. Another reason that might cause this includes an overheating engine, which destroys the gaskets or the cylinder head.

Signs That Oil Is Present in Coolant

oil in coolant causes

Unsure if oil and coolant have mixed? Here are some of the things that can happen, which are also indicators that you must do something before the problem escalates:

1. Discoloration 

One of the best things to do is to inspect closely and notice any visible color change. You will find a milky brown sludge when the problem happens. If it is an early stage, you will most likely see a sheen drop of oil. The longer and the worse the problem gets, the more apparent the discoloration is. 

2. Coolant Loss

Coolant loss is another sign that there is coolant in the oil. Even if there are no leaks in the exhaust pipes, the antifreeze can drop continuously. Checking the oil level is the next step. If it drops significantly, chances are, such is because of its mixture with the coolant. 

3. Weird Smell 

An unusually sweet smell when you open the hood, is another indicator of oil in the coolant reservoir. This is the antifreeze leaking. Another thing that you can do is to pull the dipstick out of the engine and smell it. 

What to Do When There Is Oil in Coolant

While it is dangerous, oil mixing with coolant isn’t a desperate situation. You can experiment with different solutions, including those that we’ll talk about below:

1. Clean the Engine 

This is more of a preventive measure than an immediate solution. The more often you clean the engine, the easier it is to spot potential issues, such as blown gaskets or leaking transmission cooler. This means that you can execute the necessary solution immediately before oil and coolant can mix. 

2. Do a Pressure Test 

A pressure test kit is a handy tool for engine care and maintenance. It puts pressure on the coolant so you can detect any sign of malfunctioning. Nonetheless, the equipment needed to perform this confirmatory test is quite expensive. Some people find it better to go to the nearest auto shop to have the test done. 

3. Use the Right Oil and Coolant 

The wrong choice of oil and coolant can result in the deterioration of the different engine parts. Such will increase friction in the moving components, resulting in premature wear. With such, you must use top-notch oil and coolant to ensure peak functionality. Even if they are expensive, your priority should be quality over cost. 

4. Consult with a Pro 

Especially if you are not a handyman or do not know a lot about engines, your best bet is to go to a local auto repair shop. Here, a licensed mechanic will look at your engine to confirm the problem, and more importantly, to execute the necessary solution. Find a reputable professional to take care of the issue. 

5. Replace the Damaged Parts

If it is too late to act, you will be left with no other option but to replace the damaged parts. From the head gasket to the air cooler, you might need to change the different components that are crucial for your engine to work effectively and efficiently. Otherwise, it can lead to more serious issues, which can also compromise safety and performance. 

Frequently Asked Questions – Oil in Coolant

oil in coolant fix

Before ending this article, here are the answers to some questions that most of you might have about oil in the coolant:

What Is the Function of Oil in Cars?

The oil acts as a lubricant, making it one of the most important in ensuring a vehicle’s overall performance. It allows smooth movements of the engine’s moving parts. Without oil, there is too much friction and heat. The right oil minimizes wear and tear while also improving efficiency. 

What Is a Coolant? 

Antifreeze or an engine coolant does not only prevent the engine from freezing. It also defends against rust and corrosion, making the engine longer-lasting. Plus, it removes heat. 

What Does Oil in Coolant Look Like? 

A coolant that mixes in oil looks thick and milky. It has the same consistency as gravy. It also has a milky color, although in some cases, it will leave a red, orange, or green mark in the crankcase. 

Can I Drive a Car with Oil in Coolant? 

If the problem is starting, there should be no need to worry. However, when there’s a lot of oil in the coolant, avoid driving your car. Otherwise, you might end up significantly damaging the engine. Repair and replacement will be costly. 

How Much Does It Cost to Fix Damages from Coolant in Oil? 

The exact amount depends on different factors, such as the extent of the problem, your location, and the mechanic. In most cases, it will range from $4,000 to $8,000. The more expensive and advanced your vehicle is, the more the service will cost. 

Conclusion – Oil in Coolant 

The presence of oil in engine coolant is a problem that you should not take lightly. A slight drop may not be alarming, but if they mix to the point of discoloration, you should act quickly. Otherwise, it will be too late, and you have no other option but to take the burden of expensive repair and replacement. 

Different factors can result in having engine oil in the coolant. As mentioned above, such can be because of the following:

  • Damage head gasket,
  • Malfunctioning of the air cooler, leak in the transmission,
  • Crack in the engine, and
  • Overheating.

Meanwhile, the potential solutions include keeping the engine clean and working with a professional to diagnose the extent of the problem and recommend the necessary solution. 

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