When you open the oil cap in the engine bay for the regular oil change, you may find white stuff under the oil cap. While this car issue isn’t harmful, it indicates how one has taken care of the vehicle. It doesn’t indicate a serious concern. However, it requires an inspection to ensure other issues don’t persist.

It may indicate condensation or water mixing with the oil. Speaking of that, learning about the milky oil cap causes is essential to solve the issue. Let’s go through the creamy oil filler cap symptoms, the reasons behind it and how to fix the problem.

What Is the White Stuff Under My Oil Cap?

While most issues may seem harmless, they can eventually give rise to common car problems negatively impacting the vehicle’s overall performance. A prime example of this is white stuff under the oil cap. However, if condensation is one of the causes of white stuff under the oil cap, water must have entered the engine, and it may cause several other problems.

Here are all the causes of yellowish or white stuff under the oil cap.

Condensation

In some cases, the white stuff under the oil cap is due to condensation or moisture accumulating inside the engine. It is more likely to occur in colder climates or during short trips where the engine doesn’t reach its full operating temperature, allowing water vapour to condense and mix with the oil.

Oil and Coolant Contamination

One possible cause of the white substance is coolant (antifreeze) mixing with the engine oil. It can be a symptom of car coolant leaking due to a blown head gasket, a cracked cylinder head, or a faulty intake manifold gasket. The coolant can enter the oil passages, leading to a white, milky appearance under the oil cap.

Excessive engine blow-by

It can be a symptom of worn-out piston rings or a faulty positive crankcase ventilation (PCV) system. Excessive blow-by gases can escape into the crankcase and cause the oil to become contaminated, leading to the appearance of milky stuff under the oil cap.

Leaking head gasket

Overheating is one of the causes of a blown head gasket. It can result in a mixture of coolant and oil, leading to a sludgy substance forming under the oil cap.

Incorrect oil type

Using the wrong type of car engine oil for your specific engine can cause issues, including the formation of sludge and emulsification. That’s why it is essential to choose the correct type of oil.

Symptoms of White or Milky Stuff Under the Oil Cap

The white stuff under the oil cap can be associated with certain symptoms that may indicate underlying issues in the engine. Here are some common symptoms you might notice:

Overheating

If the white substance is a result of coolant mixing with the oil, it can lead to overheating of the engine. Coolant helps regulate the engine’s temperature, and if the levels drop due to a leak, you may see a fluctuating car temperature gauge. Moreover, it causes some common car issues due to excessive heat.

Loss of Engine Performance

Contaminated oil can hinder proper lubrication and reduce the engine’s performance, power or cause rough idling and decreased fuel efficiency.

Sweet Smell from Exhaust

If coolant is burning in the combustion chambers due to a head gasket leak, you may notice a sweet smell from the exhaust.

White Smoke From Exhaust

In severe cases, when the white stuff is formed under the oil cap, it can be the reason for white smoke from the exhaust. It indicates significant coolant leakage into the engine.

Fixes of White Stuff Under the Oil Cap

If you find a milky substance under the car’s oil cap, here are the possible fixes: 

Drive for a Longer Period

If the car doesn’t have any mechanical problems, you must start driving for a longer period. Since a short drive doesn’t allow the car to reach its optimal temperature, a drive for a longer time can help fix the building of white stuff under the oil cap.

Clean the Engine Bay

One of the essential benefits of cleaning the engine is it helps remove the residue, such as a milky substance, under the oil cap. Follow the tips to wash the car engine at home and avoid issues that may cause a bigger problem.

Repair or Replace the Head Gasket

A blown head gasket can be the cause of coolant and engine oil mixing. Therefore, replacing the head gasket can help fix the problem of white stuff under the oil cap.

These were all the causes and fixes of white stuff under the oil cap. When you buy a used car in the UAE, inspect the car completely. Check the engine oil cap and other components for any wear and tear before buying a vehicle.

Stay tuned to the dubizzle autos blog to learn more about minor and crucial car problems and how to fix them.