Preparing a Pressure Washer For The Winter

Whether you call it them pressure washers or power washers, these are darned handy machines to have around. For portability, we use models with a gasoline engine and are on our second one. The first lasted for a few years until one wither the water in the pump turned to ice and finally cracked the housing. As they say “and that was that”. I thought about just buying a pump but for a little bit more we bought a whole new unit. My friends also cautioned me to always winterize the unit to make it last through Michigan winters. That was 6-8 years ago and I have learned a few tips to share.

By the way, the photo above really is of our pressure washer. I don’t have space to store it indoors so I really do need to Winterize it. Regardless of the brand you buy, there are three things I would tell you to do.

Drain the gas and/or use a mix with Stabil

Assuming you have a gasoline pressure washer, you might want to drain the gas from the tank and run the unit until it stalls. There are two reasons for this – gas can spoil if left untreated and also, when it evaporates out of the carb it will leave a gummy residue that may need to be cleaned out. In my case, my washer only sits idle a few months so I don’t always drain it. I’ve not had a problem so far. I always drain my chain saws because they may sit an unpredictable amount of time.

The second recommentation that you can do along with the first is to always add Stabil, a gasoline conditioner, that keeps it from breaking down for at least 12 months. I always add it to all of my gas cans when I fill them.

Blow out the system and disconnect the gun/wand and hose

What did in my first pressure washer was not draining the water out of the pump. I made a small air fitting by taking an old piece of hose and a 1/4″ air fitting that I can screw into the pressure washer and blow all of the water out of the pump, lines and wand. It works great.

I just use junk hose to make the adapter. You just need a male hose fitting on one end and a way to connect your compressor on the other.

If you really want, you can buy pre-made winterizer fittings for $12-20. The above fittings were all made with old stuff I had laying around.

Drain The Soap Tank

Don’t forget to drain the soap tank also. You don’t want it to freeze and crack anything. I did forget this one year and had to rebuild the fitting that cracked with epoxy.

Don’t forget to drain the soap from the plastic soap tank.

Add a Winterizing fluid

I then use an aerosol based pump winterizer. It can blow the water out by itself technically but I’m paranoid. I use my compressor to blow out everything and then I disconnect the air lines and wand/gun. I then connect the Briggs & Stratton 6151 Pressure Washer Pump Saver Anti-Freeze and Lubricant to further protect against freezing and to lubricate the pump and prevent the O-rings and seals from drying out. This works great for me and one can will last me 2-3 years at least.

This is what I use and have never had a problem.
All you do is connect the hose assembly to the hose inlet and push the trigger. The foam will come out pretty quick – it doesn’t take a lot. Note, stand to the side or you will wear the foam. I kid you not that it took me two years of wearing foam until I remembered to stand to the side when filling the unit with foam. Also, remove the hose and wand/gun before doing this or you will use a lot of material to purge them also. You can blow them out or even hang and drain them vs. using this stuff unnecessarily.

Now a ton of reputable companies sell some form of pump protector / winterizer. I suspect one or two companies actually make it and then applies different labels – Generac, Briggs & Straton, Stabil, etc. Just go with a name brand and I bet you will be fine.


I hope this helps you out. My current pump is still going strong even though it is out in the winter weather every year. The paint is fading but it is mechanically solid.

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