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Pressure Washing Do’s and Don’ts

March 02, 2017 by K

DON’T let your fuel go stale, DO add Ethanol Shield

After ONLY 30 days of downtime the fuel in your gas pressure washer may turn stale. It is important to always stabilize your fuel to prevent moisture from leaching into your fuel. Some people recommend that you drain your fuel and 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 contamination, 1 bottle (2oz) = good for 5 gallons of gas.

Most SIMPSON pressure washer models have a 1/2 gallon tank. You will need to pour 1/2 oz. Ethanol Shield into your tank when tank is FULL of gas. By taking care of your engine, you will extend its life and protect your investment.


DO winterize your Pressure Washer, DON’T forget Pump Guard

If you did not winterize your SIMPSON, some residual moisture in your pump can expand in cooler months, causing tiny cracks in your pump. Winterizing will prevent any residual moisture from freezing, expanding and potentially cracking valves and seals inside your pump.

You will need Pump Guard for every season thereafter. Follow your user’s manual for instructions and refer to our “How to Winterize Your Pressure Washer” blog for helpful tips!


DON’T use ill fitting nozzles, DO replace broken nozzles

Your SIMPSON may be operating in low-pressure due to an incorrectly sized nozzle or a nozzle that has worn out.

Always replace any worn or broken nozzles as they can potentially be a safety hazard.

ALWAYS use accessories that are within your pressure washer’s PSI range. You could be losing pressure because your accessory is meant for a higher/lower PSI range than your machine and can cause damage to your accessory.

Be sure to check if the water is fully turned on and there is enough water flowing through the pump. Check your pumps filter on the inlet to make sure there is no debris blocking the water flow. A hose that is vertical or too long may delay water pressure from arriving fast enough.


DON’T use hot water, DO use cold water

If you have a hot-water and cold-water outdoor faucet, make sure to always use the cold water for best results.

If you don’t have a hot water faucet, water that has been trapped in a hose with sun directly on it may be enough to cause your pressure washer to run a bit rough. If this happens turn off your machine, disconnect hose, and let water run until it is cold.

You may also check your air filter inside of your engine to be sure that it is clear of any debris.

If all looks good and you aren’t using hot water, then you may have mechanical damage within your pump and will need to call SIMPSON’s technical support line.


DON’T let your SIMPSON overheat, DO use your Thermal Relief Valve

If you let your pressure washer run for longer than 2 minutes at a time it will enter into bypass mode. This means that the water inside of the pump is continually flowing and heating up. When your pump is too hot it will cause damage and can potentially crack. To prevent the pump from over-heating, your SIMPSON is equipped with a thermal relief valve (safety feature only) that will release hot water when the pump becomes too hot.

Be sure to turn off your machine if you take breaks longer than 2-3 minutes.

If your pressure washer is leaking at the gun, wand, or nozzle it could be that your accessories are not secured tightly enough. Turn off your machine and ensure everything is tightened properly.



25 responses to “Pressure Washing Do’s and Don’ts”

  1. Dorene Peters says:

    What is the best type of gas to use in the pressure washer. Do I need to use ethanol free gas?

  2. Jake Ewing says:

    Good stuff, keep it up!



  3. Paul Guida says:

    How often does the pump oil need to be changed? Is there a dip stick to check the level? I did not receive the sample pump guard with my new power washer. I am a little paranoid about the pump, since my last one had two go within 5 years, Generac brand. Any tips that I need to know?

    Thank you,


    • SIMPSON says:

      Hi Paul,

      The pump oil schedule is specific to the pump and this info will be located in the owner’s manual that came with your pressure washer. Also, if you want pump guard, we offer it. You can find it on our accessories page. I hope this helps! Happy washing!

      SIMPSON Team-KW

  4. Very nice, It’s a one-stop blog for pressure washer maintenance. In my experience, one of my friends has pressure washing machine and he uses less often, which means seasonally. Then he called Canadian Power Systems because he is unable to handle its maintenance. Its crew performed well and offered full guidance on it. Could you guys also provide immediate pressure washer service?

    • SIMPSON says:

      Hi Timwillimason,

      If you call our customer service department at 877-362-4271 they will direct you to the nearest service center to repair a SIMPSON machine.

  5. Brian B says:

    Brand new PS3425 from TSC and the pump is bad right out of the box, and the closest service center is 40 miles away. So frustrating. How well back to college football, sidewalks and patio can wait a little longer.

    • SIMPSON says:

      Hi Brian B,

      We are sad to hear the PS3425 did not work for you.We are sorry for the inconvenience this has caused you. We want every customer to receive products and services that exceed all expectations. Clearly this time around we have failed with you while using our PS3425. We understand how frustrating this can be and we know apologies don’t fix the past. Please give us a second opportunity to show you what we are truly made of.

  6. Ed Stevens says:

    I bought my Simpson back in August and used it for the 4th time today. The thermal release value is constantly releasing water. I let the washer sit for 4 hours and turned on the hose and it immediately started spraying water without the unit running.
    What do I need to do to get the this fixed, or what do I need to do?

    • SIMPSON says:

      Hi Ed Stevens,

      Sorry for the inconvenience this has caused you. We are always hard at work to make sure our team delivers on our brand promise and every customer has a positive experience. Please call our customer service at your earliest convenience at 877.362.4271 and they will get this resolved for you.

  7. Paul Baird says:

    How much pressure will just using the unloader relieve? I have a 3400psi machine and just curious if I open the unloader how much pressure can be expected to drop.

  8. abe ruben says:

    Just purchased a Water Blaster 60828 and 60827. Was wondering if you have any tips on how to best prep the engine before first use and thereafter.


    Curious User

  9. Robert Smith says:

    I just purchased a Simpson Premium Pressure Washer from Ollies Discount store. It is a 3000 PSI 2.4 GPM unit but the only manual that came with it was how to put it together after un-boxing and danger warnings but the model number and other identification had been removed or blacked out. Is there any way that I can get a more detailed manual for use and maintainance? I am located in the Detroit Michigan metropolitian area.


  10. Dimitri says:

    Hello there, I just bought a new 3200psi Simpson pressure washer. Is it OK if I use ethanol free gas only?
    Thank you in advance

    • SIMPSON says:


      Use of fuels with greater than 10% ethanol are not approved for use in this product per EPA regulations and will damage the unit and void the warranty.

  11. Joselin says:

    I just perchas a pressure washer 3400 psi 2.5 gmp I was wondering if I can use regular gas or I have to use gas with 10% ethanol

    • SIMPSON says:


      unleaded gasoline with a pump octane rating of 86 or higher.Use of fuels with greater than 10% ethanol are not approved for use in this product per EPA regulations and will damage the unit and void warranty.

  12. Ralph says:

    Hello. I was power washing my pool pavers and lanai cage today. After shutting the machine down, I noticed a small flame coming out of the exhaust. I’ve had the power washer a year and have a total of 32 hours use.By the way, I have followed the maintenance schedule and have had no problems. Is there a reason for this occurrence and how can I prevent this from happening again? Thanks.

  13. Rob says:

    “DON’T let your SIMPSON overheat, DO use your Thermal Relief Valve”
    Is the thermal relief automatic? It is on other brands.
    It is advisable to use pretreated fuel and NEVER use untreated fuel in a small engine.
    I DO like the fact I can buy your pressure washers with a Kohler engine.
    I do have a different brand machine, but uses the same pump as you use, I use the Pump saver after each use, prevents mineral build up and keeps pump “lubricated” between uses.

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