What To Do If Your Pressure Washer Pump Oil Is Milky



After a long day in the field, professionals in transport, waste management, or agricultural industries endeavor to service their trucks and equipment. Top on the list is a thorough clean-up using a pressure washer.

That said, a poorly maintained or defective pressure washer can cause a delay in your daily routine. One common problem many pressure washer users notice is milky pump oil, which can compound into expensive repairs that affect your bottom line. It's crucial to fix the problem urgently to mitigate further damage or loss.

is your pressure washer pump oil milky?

This is not an entirely uncommon problem, but left untreated, it can lead to expensive repairs. Let's explore its causes and ways to solve the problem.

Causes of Milky Oil in Your Pressure Washer's Pump

The main reason your pressure washer has milky oil in the pump is that water is seeping into the oil gasket. Nonetheless, other factors contribute to the situation.

Below is a breakdown of the causes in detail.

  • Excess Humidity: Excess humidity in the air results in condensation of water in the oil casing, which ultimately seeps into the oil gasket. The possibility increases in high humid areas and when a pressure washer lies idle for an extended period. Alternatively, as the pump cools down, it draws in humid air, which condenses into water. Continued exposure builds up the percentage of water, which eventually turns the pump oil milky.
  • Damaged Oil Seals: The role of the seal is to prevent liquids, dust, and unwanted elements into the oil compartment. When the seal or washer is damaged, water seeps in with ease. Seals become damaged due to poor pressure washer maintenance, thereby exposing the oil to water. If the pressure washer has damaged oil seals, exposure to rain leads to leaking. Water applied during the washing process can also leak, leading to milky oil.
  • Damaged Water Heat Exchanger: Several pressure washers use water as a coolant medium. As the equipment ages, the internal tubes degrade, making it possible for water and oil to mix.
  • Crack in Plungers: A plunger functions like pistons found in vehicle engines; the only difference is they are protected and move in a closed cylinder. Cracks in plungers expose oil to humidity and water used in the cooling process. When the crack is not detected or repaired on time, you'll have a constant problem with your pump oil.

how to fix milky pump oil

The process of fixing the problem is an elaborate process that requires opening the pump, emptying the milky oil, replacing the packings, and adding some fresh oil. Below are the two main approaches you can use:

1. Disassembling the Pressure Washer

Besides replacing old seals, you need to disassemble the pump to check whether everything is intact, including the oil gasket.

Here's a step-by-step breakdown.

  • Take off the Casing: Use a wrench to unscrew every bolt in the exterior casing. Carefully remove the bolts and place them safely in a bowl. The unbolting process will make it easy to remove the case.
  • Remove the Allen Socket: After removing the casing, the interior parts of the pressure washer will be visible. Use a wrench to remove the Allen socket and get a clear picture inside the pump case.
  • Remove the Valve: After successfully locating the pump case, you'll find a valve inside the casing. Use a pair of forceps to remove it — take caution to avoid damaging this crucial element.
  • Open the Casing: Strike the casing with a hammer carefully, to open the case into two. The process will enable you to see the oil rings.
  • Repair the Oil Ring: After opening the casing, you'll notice the packing, leaking oil, and water. You can either apply re-seal to restore permeability or change the entire packing.
  • Re-attach the Pressure Washer and Add Oil: Once you've repaired the damaged components, you'll need to re-assemble the pressure washer. The final process requires you to add fresh oil with the pump in an upward position.

2. Replacing Worn-out Packings

A worn-out packing is one of the reasons water permeates into the oil gasket of a pressure washer. Packings are affordable to acquire, and the replacement process is equally easy — extreme weather can damage them by causing uneven contraction and expansion.

Here's how you can replace the worn-out packing:

  • Purchase the Right Packings Kit: Refer to the pressure washer user manual to get details of recommended packings model and size. Look keenly at the dimensions to ensure they're a perfect match.
  • Replacement Process: Use an Allen wrench to remove bolts at the back of the pump, followed by brass rings above the packings. Examine each packing to identify the damaged ones.
  • Replace the damaged packings with new but perfectly fitting sets. It's crucial to handle brass rings carefully, as they can easily damage.

A point to note: You can always talk to a pressure washer maintenance professional to help you in the process of replacing worn-out packings to eliminate errors.

valuable tips for repairing or maintaining a pressure washer with milky oil in the pump

Replacing Contaminated Pump Oil: Climate is a significant factor that can make a pressure washer develop milky pump oil. It's therefore essential to select suitable oil — for instance, 15W40 or 15W30 oils are ideal for cold or winter climates. The ideal oil should enhance performance and prevent excess contraction, which can create sufficient space for condensation. You should also fill the oil to the right level — usually three-quarters full.

Alternative to a New Packing Kit: Depending on your budget or experience, you can try repairing an old packing kit. The method can offer an immediate solution; however, new packings can provide more durability. Alternatively, you can use re-sealers to restore the waterproof profile of the worn-out packings. The ideal size depends on the damage to the packings — extensive wear and tear require thicker and stickier re-sealers.

Cracks in Plungers: Cracks that occur in plunger cylinders sometimes result in milky pump oil. The remedy to this problem is to involve a highly skilled welder to seal off the defect. Such a repair may not fully resolve the issue, so a new engine cylinder liner is the best solution

let us help you fix your pressure washer's milky pump oil

As a professional, the performance of your equipment determines your productivity and profitability. It's therefore essential to avoid a hitch like a stalled pressure washer that can delay your service delivery. 

That said, it's crucial to work with reputable maintenance and pressure washer experts like Nortex Sales & Service. We offer service in Dallas, Odessa, and Kilgore to ensure you have quick access to professional assistance.

To find out more about pressure washer maintenance, check out our complete pressure washer maintenance handbook here. 

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