Antifreeze Should Not Be Mixed With Oil – Enormous Impacts

Antifreeze and oil seems to come from two different worlds, albeit being used as fluids in automobiles.

But some drivers have wondered: Is it true that antifreeze should not be mixed with oil? The answer is yes, but the explanations of this issue are quite implicit to many.

If you are in the same boat, check our article for further information.

Antifreeze Should Not Be Mixed With Oil – What Happens Then?

Antifreeze Should Not Be Mixed With Oil

The antifreeze and oil mix has repercussions for your automobile’s health. Some common conditions, like a rough overlay of the bearings, rusting surfaces, or metal tarnish phenomenon, can arise.

Indeed, the main function of oil is to lubricate internal engines so that they can run smoothly and efficiently without any hindrances due to friction.

When the antifreeze, often used to keep your vehicle from overheating, is mixed with oil, it will result in an acidic environment.

Your motor oil will consequently be robbed of its lubricating properties, and severe engine damage to your car could be rendered.

So what are the roots of this problem? Below is a precise answer for you.

What Are The Coolant In Oil Causes?

What Are The Coolant In Oil Causes

You should pay close attention to the following primary culprits.

The Head Gasket Leak

A cylinder head gasket belongs to the internal combustion system, connecting the cylinder head and engine block.

Three fluids normally flow through this engine: oil, antifreeze, and an unburnt air-to-fuel mixture.

Suppose it is on the fritz; the engine coolant will likely leak into the cylinder or crankcase. It then dilutes the motor oil and inflicts extensive wear to surrounding engines.

Most head gasket failures are boiled down to the overheating problem caused by a malfunctioning thermostat or improperly working fans.

You should frequently check their conditions for prompt maintenance.

The Intake Manifold Gasket Leak

The intake manifold is a crucial motor part of your car, responsible for evenly distributing the exhaust mixture (with an air-to-fuel ratio) towards each inlet port in the cylinder head.

Internal coolant leaks could occur when this device is out of order, mixing with the motor oil passages through multiple pipes.

The scenario of uneven delivery is also on the horizon, while equal distribution is core to the optimal operation and performance of a car.

The Damaged Engine Block

The engine block refers to the overall structure consisting of cylinders, the cylinder block, the intake manifold gasket, bearings, and attached crankcases.

It also includes other elements, namely oil galleries and antifreeze flow.

Several parts of this system will also break down if it is prone to wear. Cylinders and the intake manifold are not the exceptions, triggering the antifreeze to mix with oil.


Overheating is conducive to the defection of various car components, such as the head gasket. As mentioned earlier, when it gets broken, the oil might be contaminated due to the coolant presence.

Some underlying roots of the overheating issue could be enumerated:

The Failing Oil Cooler

As its name suggests, the oil cooler eliminates excess heat generated during the combustion process.

Specifically, engines will transfer heat into the oil, which subsequently passes through this device to cool down.

In many cases, that it gets damaged is often shown by small cracks on its surface.

These cracks will enlarge and ruin its internal compartments if the problem persists. The engine coolants will leak out via these holes before being diluted with the oil.

Other Factors

The list of agents as follows is least happening, yet you still need to be on the alert: 

  • Degraded seals
  • Electrochemical rusting
  • Oil fouled spark plugs
  • Thermally cracked cylinder heads
  • Head bolts being incorrectly torqued
  • Blown gaskets
  • The cylinder liners vulnerable to the cavitation corrosion
  • The oil’s bad quality
  • The clogged fuel filter

What Are The Symptoms Of Antifreeze In Oil?

What Are The Symptoms Of Antifreeze In Oil

Antifreeze Loss

Many drivers are reported to encounter this sign. It is attributed to the coolant leak that an amount will flow into the crankcase and mix with the oil.

Given this situation, you easily see continuous antifreeze drops on the ground while the exhaust pipes are not cracked.

If you don’t notice any, check the engine oil to see whether there is an increase in the fuel level.

The Sweet Smell

The antifreeze’s smell is quite sweet, like a candy-coated aroma. Hence, all you need to do is open the crankcase and pull the oil dipstick to stir evenly.

Even a small amount of coolant mixture can give off this iconic sweet odor.

The Milky Color

When the antifreeze initially gets into the oil, it will form different colors, like orange, green, brown, or red, depending on the oil condition.

But when you start the engine, the antifreeze and oil will be mixed together, creating a milky, creamy texture that you can simply identify with the naked eye.

How To Solve The Antifreeze In Oil?

How To Solve The Antifreeze In Oil

Here are feasible remedies to each of the causes above that you could apply if needed:

  • If the cause lies in a bad head gasket, you should instantly replace it with a new one. Remember to purchase a new gasket from a reliable store, so its lifespan extends.
  • When the whole engine block gets into trouble, call for a qualified mechanic, and he will check your automobile’s overall state.
  • Suppose the temperature in your car reaches too high; take a quick look at the cooling system to see if something is wrong with its components.
  • Should you have enough knowledge in the automotive field, you can examine your car at home. However, this practice is not highly recommended, as it might threaten drivers’ health and safety.

Frequently Asked Questions

How Much Does It Cost To Fix The Coolant In Oil?

The cost of replacing one failing engine is only 400 to 500 dollars. But if your car is seriously ruined, the figures may climb up to 4000 and 8000 dollars.

Can You Drive A Car With The Antifreeze In Oil?


If you detect something abnormal, you should stop driving at all costs because the oil and coolant mix wreaks great havoc on your vehicle’s engines.

Can A Bad Water Pump Cause The Antifreeze In Oil?


Although the water pump is a part of the cooling system, it is only used to force water through the radiator and hoses. So it does nothing to the problem of antifreeze being diluted with the oil.

The Bottom Line

Hopefully, this article helps you understand more about the reasons why antifreeze should not be mixed with oil.

Take note of all the causes to sidestep them and if you accidentally mix them, act as soon as possible.

Thank you for being supportive, and have a nice day!

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