Lawn Mower Engine Oil Turns Milky-Fixed

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If you notice that your lawn mower engine oil suddenly turns milky, it can be attributed to two things: it is either the engine oil has been contaminated or you have an engine problem on your hands.

Can you fix the milky oil problem? Yes, you can.

In this article, I share common causes of milky engine oil and how to fix them.

What Does Milky Oil in Lawn Mower Engine Mean?

Generally, milky mower engine oil means that your engine oil has mixed up with either water or antifreeze.

The color of your engine oil can show the cause of its contamination. The oil that is contaminated by water will appear whitish, while oil that is contaminated by antifreeze will appear greenish.

Lawn Mower Engine Oil Turns Milky: Causes and Fixes

Two main factors might be responsible for your mower’s engine oil getting milky.

1. Water 

If your engine oil color is creamy whitish, it might be as a result of water from condensation. Condensation is the most common cause of milky engine oil, especially in air-cooled engines.

Fix:  Turn on your machine and allow it to warm up. The milky color should clear off once your engine is warm.

2. Anti-Freeze

When your engine oil mixes with antifreeze or coolant, it gives it a milky texture in a greenish, brown, or orange color, depending on the brand of the oil. The presence of coolant in your engine oil will cause it to lose its lubricating power, which might lead to engine damage.

There are different reasons that your engine oil can get mixed up with a coolant, and they include;

  • A cracked head gasket

The Head gasket is usually the cause of oil and coolant mixup because the crankcase is the most common area where coolant gets into the oil. 

White smoke from the exhaust pipe can indicate a cracked head gasket.

Fix: You can have a mechanic repair your head gasket or get a new one.

  • A leaky head cylinder

The head cylinder usually prevents antifreeze from mixing up with the engine oil, but if it starts to leak, antifreeze and engine oil might eventually get mixed up.

Fix: Replace your head cylinder. Please note that you shouldn’t do this yourself unless you are a professional mechanic. If not, contact your mechanic to help you replace the damaged head cylinder.

  • Overheating

If your engine starts overheating, it might damage your head gasket or cause it to leak, leading to your coolant and your engine oil getting mixed up.

Fix:  Put off your engine and let it cool off.

Next, check your coolant. If your coolant is dirty, drain it and replace it with a clean one.

Next, drain the contaminated oil, replace it with a clean, and run your mowing machine. 

Repeat the process until your oil is clear. 

  • Damaged engine block

 Although this is relatively uncommon when your engine block is damaged, it can cause antifreeze to mix up with your engine oil.

Fix:  You can either repair your engine block or replace it.

Should You Use Your Mower With A Milky Oil?

No, you shouldn’t. When your engine oil gets contaminated through water or antifreeze, it loses its lubricating power and will not lubricate the engine properly. 

Using your lawn mower with milky oil will cause friction, heat, and wear, leading to engine failure.

How To Drain Oil From Your Mower

When your lawn mower’s engine oil is contaminated, it becomes crucial that you drain it. It is necessary to drain the contaminated oil before replacing it because not doing so might damage your engine. 

How to Drain Oil from your Lawn Mower: Simple Steps to Follow

  • Step 1: Warm up your engine by starting and letting it run for a while. Warming up your machine before draining its oil will allow the oil to drain entirely with any impurity it might contain.
  • Step 2: Put the mower in the correct position. The proper position is where the dipstick is close to the floor.
  • Step 3: Remove the dipstick cover and tip the mower until the oil begins to drip.
  • Step 4: Hold your mower and allow the oil to drain completely.
  • Step 5: Lower your mower back to the floor. Clean any excess oil and fill the dipstick can with clean oil.

How To Get Water Out Of Your Mower

You must drain your oil and gas tank to get water out of your mower. To remove the water in your mower, follow the following steps:

  • Step 1: Take out your gas tank.
  • Step 2: Remove all the gas in it, along with any water
  • Step 3: Shake the tank until it is empty. 
  • Step 4: When the gas has been completely drained, add a little gas into the gas tank, shake and drain again.
  • Step 5: Repeat the process until you have gotten rid of all the water

Lawn Mower Maintenance Tips 

You can perform certain routine checks on your lawn mower to prevent its engine oil from getting milky, and detect it on time  even if it does.

  • Check your dipstick after running your engine: Make it a habit to open your dipstick can and check the state of your engine oil after each mowing session. This way, you can quickly detect when something is wrong.
  • Cover your mower when not in use: You want to ensure that you are not exposing your machine to water. Don’t leave your mower in the rain, cover it when it’s not in use.
  • Check your engine parts regularly: Always run a routine check on your mower’s engine, especially the head gasket, head cylinder, and engine block. A regular check on your engine will help you quickly discover if anything is damaged or blown so you can fix it before they cause more damage.
  • Use only recommended oil for your engine: Different lawn mower brands have different types of recommended oil. This is why you want to ensure you are using the right oil for your mowing machine.


Milky engine oil in itself is not a cause for alarm; however, you shouldn’t ignore it either because it might indicate a bigger engine issue.

Check your engine to determine what might be the cause of its milky oil and follow the steps listed in this article to fix it.

However, if the problem persists after correctly following the steps above, you should call your technician because it might be a bigger engine problem.