The dipstick is used to check the level of oil in your engine. Pulling out the dipstick to read the oil level and seeing bubbles indicates that froth has formed in the oil tank. Bubbles can form when the oil is overfilled, when coolant leaks, and for various other reasons.

Bubbles on the dipstick may indicate a serious problem with the engine. This article will go over the various reasons you might see bubbles on your oil dipstick.

What causes oil to bubble?

When engine oil is stirred and aerated, it bubbles or froths. If there is a variation in temperature and pressure, air can enter the oil and create bubbles. This is due to the oil’s high volume, which causes air bubbles to form inside the oil.

Additionally, when oil is combined with chemicals from other liquids, bubbly milky froth can form. When you check the oil level, this bubbly oil can get onto the oil dipstick. We’ve seen cases where the dipstick is dry. Let us look at some possible causes of bubbly oil on the dipstick.

What causes Bubbles on the Oil dipstick?

1. Overfilled Oil

Bubbles or foam can form in the oil when the oil level in the engine is too high. A quick-moving lobbed rod called a crankshaft is what the engine uses to rotate. When oil is overfilled, the crankshaft stirs and aerates the oil. 

The oil begins to foam and bubble due to the constant churning. These bubbles will appear on the dipstick when you check the oil level. Drain any extra oil to prevent the crankshaft from rotating in the oil and lower the level of the oil pan.

2. Blown Head Gasket

Head gasket seals are important to seal the combustion engine properly. There is a chance that the coolant will mix with the engine if the head gasket blows. When this coolant is combined with oil, a milky froth-like film may form on the oil.

You will notice light brown bubbles on your dipstick when you check the oil. Ensure the head gasket is repaired to prevent coolant from leaking into the engine oil.

3. Cold climate 

If you live in a cold climate, it’s common for air particles to enter the engine. Low-temperature engine oil can trap these air particles and create bubbles. This bubbling may produce froth, turning the oil milky

Long car rides frequently cause these air bubbles to pop out as the engine oil will heat. Therefore, it is advised that you occasionally drive for 30 to 60 minutes.

How to fix bubbles on an oil dipstick?

There is froth formation in the oil tank if you notice bubbles on the oil dipstick. In that situation, it is best to drain the old oil. Remove the drain plug to empty the oil. Make sure the engine is just warm enough. This will thin the oil and make it easier to drain out of the container. Additionally, you can use a vacuum cleaner to remove all traces of bubble oil.

Tips to avoid bubbles on the oil dipstick

  • Avoid overfilling the oil in your dipstick to prevent bubbles. Verify that the oil level is below the fill line and that the dipstick isn’t all covered in oil.
  • Fix the head gasket to prevent coolant from leaking into the engine oil.
  • Make sure to go on long rides if you live in a cold climate. Oil will heat up, as a result, causing the air bubble to burst.

How Do You Check For A Blown Head Gasket?

Coolant and engine oil may mix due to a blown head gasket. When checking the oil level in the engine, this may result in bubbles on the dipstick. Examining the interior of the oil fill cap is the best way to look for a blown head gasket. The head gasket has likely blown if the filler cap has some brownish milky substance on its interior.

How do you remove air from engine oil?

It is normal for air to enter the oil. When oil is cold, air can become trapped inside it.  This air can pop out of the oil when oil is heated. Take long drives in your car to accomplish this. Every three to five weeks, you are advised to drive your car for at least 30 to 60 minutes.


To sum up, there are a variety of causes for a dipstick bubble. This might result from a coolant leak in the oil or an overfilled oil tank. Additionally, air particles easily become trapped in oil if you live in a cold climate, resulting in bubbles in the oil.

The engine may overheat and experience friction problems due to bubbles in the oil, causing improper lubrication. It is best to drain the old oil if you notice bubbles on the dipstick. Before adding new oil, fix the head gasket if it is blown.

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