Why Is My Dirt Bike Oil Milky White?

Just find milky grey looking oil in your dirt bike? It’s not normal, so you need to get it fixed as soon as possible. 

In this article I’ll show you what milky oil in your 2 stroke or 4 stroke means, the most common causes, and how to fix it. 

What Is Milky Oil?

Milky oil is usually grey or dirty white colored oil that has a thicker consistency. Depending on the oil temperature it may look like a sludgy milkshake. 

Milky White Oil Why Is My Dirt Bike Oil Milky White?
Milky oil contaminated from water.

What Does It Mean When Your Dirt Bike Oil Is Milky White?

Milky oil means that water has gotten into and mixed with the engine oil. This could be straight water or coolant from the engine cooling system. 

How To Check For Milky Oil

The easiest way to check for water in your oil is to drain it and see if it’s milky. 

If there’s a lot of water or coolant mixed in, you might be able to see it on the oil dipstick or sight glass

Milky Oil In 2 Stroke Dirt Bike

There’s only two common reasons why a 2 stroke would have milky oil. 

A 2 stroke only has transmission oil/fluid in the bottom end, which is separated from the top-end of the engine. 

When you drained the oil, did it look like mostly oil or was there a lot of water mixed in?

Check Coolant Level

Is there a lot of water in the oil? Check the coolant level in the radiator if it’s cooled down. 

If you can’t see any coolant, there might be a leak. This is often from a bad water pump oil seal. This seal keeps the coolant in the cooling system separate from the oil. 

Some dirt bikes have a little weep hole on the water pump cover that will drip a little bit of coolant when the seal has failed. 

Always remember to use aluminum-safe coolant in your dirt bike to protect the rubber seals. 

You Fell In The Drink

Another common reason for water in the oil is if you drowned your dirt bike. This could be from tipping over in a river crossing, a pond, creek, or any body of water. 

If the engine or intake gets covered in water or mud for any amount of time, you risk sucking up water into the engine. 

It probably won’t immediately cause damage, but you need to drain and flush the water out as soon as possible to prevent issues in the near future. 

Water that got sucked in can get into the engine oil, thus turning it milky grey. 

If there wasn’t much water that got in, you can usually drain the oil and flush it out 2-3 times and it will be fine. 

You Blew A Gasket

A blown head gasket can also result with coolant in the oil of your dirt bike. 

A bad head gasket will often suck a lot of coolant through the engine. If you have to keep adding coolant to keep the level up, stop riding and inspect before there’s a major problem. 

A blown head gasket can show up as overheating, steam out the coolant overflow, or a lack of power. 

Bottom Line

  • Check oil if coolant is low
  • Stop riding and inspect if coolant is low every ride
  • Drain water and flush if bike was drowned
  • Don’t ride with milky oil unless in emergency

Kelley Fager

I help riders learn to safely ride off-road with confidence so that you don't crash and get injured, even if you don't have a lot of time to practice. Learn To Ride With Confidence Here

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