If the oil is milky, coolant or water may have been mixed with it. You must resolve the issue because milky oil indicates the presence of an unwanted liquid. Milky oil can cause improper lubrication in the engine, resulting in friction and overheating engine parts.

In this article, we will look at why oil appears milky brown. The engine oil will likely mix with the coolant or water if you see milky tan oil on the dipstick or oil filler cap. Let’s examine some additional indications that the engine’s oil is milky.

Milky Oil Symptoms

  • Engine overheating problems.
  • Difficulty starting the engine.
  • A white film covers the engine oil.
  • Oil smells sweet, like coolant.
  • Strange noises when the engine starts.

What causes milky oil?

Water entering the oil tank can result in milky browned oil. However, in reality, water and oil do not mix. High-speed shearing can give the impression that oil is mixing while the engine is running.

However, both layers will separate as the oil sits. The surfactants and other substances, like phosphate, give the impression of a milky film covering the oil.

Some of the reasons for milky oil are:

Blown head gasket 

The head gasket is critical in sealing the combustion engine. It properly seals the engine so no coolant gets mixed into the oil. If the head gasket fails, coolant will leak into the engine. As a result, the oil will turn a milky brown color.

In that situation, it is best to have the head gasket replaced. Labor costs are estimated to range between $909 and $1147, while parts costs can range between $715 and $832.

Moisture entering the oil tank 

In cold weather, water can enter the oil tank. Air or water vapors entering the engine through the vents cause this. Water vapor turns into liquid water and enters the oil tank when the temperature drops too low.

This is also known as condensation in oil which can turn engine oil milky. It is best to drive the car every 2-3 weeks, especially in a cold climate. The water vapors will evaporate as a result of this. 

High-pressure car wash

Water particles can enter the engine when using high-pressure pumps to wash the car. These particles can enter the vehicle through the oil filler cap, air filter, or steering cap.

Before washing the car, ensure the oil filler cap isn’t leaking and other engine parts are properly sealed. Also, use a low-pressure pump to clean the car, paying special attention to sensitive areas such as the air filter.

Other Possible Reasons

  1. A low oil level can make the oil appear milky.
  2. The oil may appear milky when checked in bright sunlight.
  3. Using an oil that is of lesser quality or that is incompatible can make the oil appear milky.
  4. Hot engine oil can have a milky brownish appearance. This will go away when the engine cools down, and then you should check the oil.

How To Fix Milky Oil In Engine?

If the oil is milky, the best course of action is to drain it and replace it with new oil. Simply removing the oil drain plug will allow the oil to be flushed. You should bear a few things in mind before adding fresh oil.

  • The head gasket must also be checked to ensure the engine is not leaking coolant.
  • Use the vacuum cleaner to clean the engine thoroughly. While using a washer and bucket is another option, but much riskier. In any case, make sure you get the water out of the engine.
  • Ensure that the engine is completely drained of all old fluid. 

FAQ’s on Milky Brown Oil

The moisture in the tank will quickly evaporate if you drive every day. If you don't drive very often, the moisture will eventually turn into water and enter the oil tank. If you live in a cold climate, this happens more often.


To sum up, the oil may appear milky if coolant or water leak into the oil tank. Engine lubrication will be improper if the oil is milky. When the head gasket blows or the vehicle is not driven frequently, milky oil may result. 

Before putting in the new oil, it is crucial to remove the old oil and thoroughly clean the oil tank. If the head gasket is damaged, have it replaced by a mechanic.

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