Sorry but you seem to be using an out-of-date and unsupported version of Internet Explorer. Please visit to update your preferred browser.

Winterizing Your Pressure Washer

September 02, 2016 by SIMPSON TEAM

SIMPSON® pump guard and ethanol shield next to the ALH3425 3400 PSI 2.5GPM Aluminum Series pressure washer

SIMPSON ALH3425 3400PSI @ 2.5GPM Aluminum Series Pressure Washer

To extend the life of your SIMPSON pressure washer proper maintenance is a must. This includes winterizing your gas powered pressure washers pump and engine for cooler months approaching. Storing your pressure washer inside is simply not enough protection. Winterizing will prevent any residual moisture from freezing, expanding and potentially cracking valves and seals inside your pump. Also, it will protect your engine from any moisture that may reside in stagnant gas causing your engine to fail.

Today we will show you how to easily and effectively winterize your pressure washer using two products that we swear by: Pump Guard and Ethanol Shield.

SIMPSON® pump guard and ethanol shield sitting in front of the ALH3425 3400 PSI 2.5GPM Aluminum Series pressure washer


Here we have the SIMPSON ALH3425 gas powered pressure washer that  is ready to be stored away for the winter months.

We will start by using Ethanol Shield to stabilize your fuel.

man pouring ethanol shield to a SIMPSON® premium pressure washer tank


Some people recommend that you drain your fuel to prevent water from leaching into it. This is a good method, but still leaves your pressure washer susceptible to moisture contamination in your tank and carburetor.

We recommend that you LEAVE your tank full and use Ethanol Shield to prevent moisture from leaching into your fuel.

 1 bottle (2oz) = good for 5 gallons of gas

Like most SIMPSON pressure washer models, the SIMPSON ALH3425 has a 1/2 gallon tank. You will need to pour 1/2 oz. Ethanol Shield into your tank when tank is FULL of gas.

man adding ethanol shield to a SIMPSON® premium pressure washer tank

hands holding up a close-up of ethanol shield directions on the back of the bottle


Connect your pressure washer to the water supply and assemble gun and hose.  Be sure that your water supply is ON and pull the recoil. Pull trigger and let engine run for 2-5 minutes to let gas into the carburetor.

Man using one hand to pull the recoil to start a SIMSON® premium pressure washer with the other hand on top of the machine


Next,  If you have used chemicals in your pressure washer you will want to flush out any residual chemicals from your pump using your siphon tube, a small bucket and some fresh water.

A siphon tube flushing out chemicals from a SIMPSON® pressure washer pump into an orange bucket


Attach your siphon tube to your pump and drop the filtered end into the bucket of water. Insert your soap nozzle into your wand and pull trigger to let the water into the pump and hold for a few seconds to a minute to flush out chemicals.

A man flushing out chemicals from a SIMPSON® pump with a siphon tube in a plastic bucket


Disconnect gun, wand high pressure hose and garden hose and drain any residual water in the hoses as much as possible to prevent corrosion and oxidation that can lead to gun, wand and hose permanently sticking together.

A man draining residual water from a hose after using a SIMPSON® pressure washer


Now, we will protect the pump by using SIMPSON Pump Guard.

A man screwing pump guard onto a SIMPSON® pressure washer pump


Using Pump Guard will coat your pump to prevent corrosion or other damage that can lead to cracks in your pump due to water expanding when frozen.

Simply remove cap and screw in pump guard to your water inlet and twist until secured. Squeeze Pump Guard bottle until there is 100% solution coming from the pump outlet. If you have trouble simply pull on your recoil a few times to help Pump Guard push through the pump.

Lastly, store your pressure washer in a dry, safe space.


Rest easy knowing your pressure washer is safe all winter long!

-The Simpson Cleaning Team

2 responses to “Winterizing Your Pressure Washer”

  1. Bernie Johnson says:

    What do I do if I cannot get the Pump Guard to go into the pump chamber and exit from the pump outlet? It seems something is blocking the pump guard from entering the pump. I have tried pulling the recoil but simply cannot get the guard into the chamber.

    • SIMPSON says:

      Hi Bernie,

      Please follow these steps:
      1) Remove the high pressure hose from the pump
      2) Install the pump guard on to the inlet of the pump
      3) Start the engine and squeeze the pump guard bottle hard until it comes out the outlet
      4) Shut off engine
      5) Remove pump guard

Leave a Reply

Your email address will not be published. Required fields are marked *