Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535

Winterizing a Pressure Washer Pump

Draining the water, putting the maker's own pump protector through the pump, and why this page names no product and no quantity
ApplicabilityConsumer pressure washers with a positive-displacement pump, a trigger gun and a garden hose inlet, electric or engine-driven, that will be stored somewhere that can drop below the freezing point of water. The pump only. Engine storage, the unloader valve and any work that opens the pump are out of scope.
Task time40 min to 1 hr 16 min editorial estimate, not a measurement
PersonnelOne
Revisionv1 · 2026-07-29
BEFORE YOU BEGIN

Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.

Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.

Summary

A pressure washer that goes into the shed in October with water still in it can be scrap by March. Water left in the pump freezes, expands, and pushes the seals and the pump body apart from the inside, and the damage stays invisible until the machine is next switched on. Kärcher puts it plainly: water expands when frozen, and seals and pump engineering can be destroyed. Generac goes further and says freeze damage is not covered under warranty. The job that prevents all of this takes about half an hour, once a year, and most of it is draining hoses.

What this page will not give you is the one thing every other page hands over confidently — a product name. That is deliberate, and the reason is that the four manufacturers we read disagree with each other in print. Kärcher says ordinary anti-freeze is insufficient and not recommended and sells its own Pump Guard; Generac names its own Pump Shield or an alcohol-free RV antifreeze; Briggs & Stratton names its own Pump Saver oil, which is not an antifreeze at all; and Sun Joe's manual accepts any non-corrosive, non-toxic anti-freeze, pump saver or pump protector. What goes through a pump is a chemical compatibility question, so we publish the disagreement, name all four makers, and send you to your own manual for the answer. This page is about the pump only — engine storage is a separate job with its own section in your own documentation, and nothing here covers it.

Safety

NOTICE

DO THIS WORK BEFORE THE FIRST FROST.
Water that freezes in the pump expands. Karcher states that the expansion can destroy the seals and the pump.

Necessary equipment

ItemNote
The manufacturer documentation for your machineThe documentation gives the storage procedure for your machine.
Protective glovesWear protective gloves when you touch the pump protector.
Eye protectionWear eye protection when you release the water pressure.
A short length of garden hoseGenerac gives a 3-foot length for this work.
A dry clothUse a dry cloth for the outer surfaces of the machine.
A label and a penWrite the date and the name of the fluid on the label.
A container of clean water optionalUse this container only for the flush of the detergent system.
The pump protector approved for your machine materialUse only the fluid that the maker of your machine approves.
Clean water materialUse the clean water for the flush of the detergent system.

Read the storage instructions for your machine

Estimated 5 min to 13 min

NOTEThe makers do not agree about the fluid for the pump. Use the instructions for your machine.
Pump protector fluid for your machine
Unverified — do not rely on this value
CONSULT THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE. THE MAKERS DO NOT AGREE, AND A FLUID THAT SUITS ONE PUMP IS REFUSED BY ANOTHER MAKER.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Four registered tier-1 sources disagree and the disagreement is published rather than reconciled. Kärcher's Pump Guard product page states that ordinary anti-freeze is insufficient in this respect and is not recommended, and offers its own Pump Guard. Generac's storage article names its own Pump Shield, part 0L2414, with RV antifreeze (alcohol free antifreeze) as the alternative. Briggs & Stratton names its own Pressure Washer Pump Saver, part 6039, which is a pump saver oil and not an antifreeze at all. The Sun Joe SPX3000 manual accepts a non-corrosive/non-toxic anti-freeze, a pump saver or a pump protector, without naming a product. Kärcher's international storage guidance names no fluid at all and prescribes draining alone. No maker is wrong about its own pump. Chemical compatibility is safety-critical under config.json, so this page names no product and no quantity: read your own storage section, and ask the maker of your machine if it names none.
Storage period before you must protect the pump
Unverified — do not rely on this value
CONSULT THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Find the storage section in the manufacturer documentation for your machine.
    • Sun Joe puts these instructions on page 13 of the manual for the SPX3000.
    • Generac and Briggs and Stratton put the same instructions in a support article.
    • If your documentation gives no storage section, speak to the maker of your machine.
    2m
  2. Read the name of the pump protector that the maker of your machine approves.
    • Karcher approves its own Pump Guard. Karcher does not recommend ordinary antifreeze.
    • Generac approves its own Pump Shield or an alcohol-free RV antifreeze.
    • Briggs and Stratton approves an oil with the name Pump Saver.
    • Sun Joe accepts a non-corrosive and non-toxic antifreeze, a pump saver or a pump protector.
    2m
NOTICE

USE ONLY THE PUMP PROTECTOR THAT THE MAKER OF YOUR MACHINE APPROVES.
The makers do not agree. A different fluid can damage the seals in the pump.

  1. Get the approved pump protector before the first frost.
    • Do not substitute a different fluid.
    1m
  2. Read the storage period that your documentation gives.
    • Generac gives 30 days for its own machines.
    • After that period Generac tells you to prepare the pump.
    <1m

Flush the detergent from the machine

Estimated 6 min to 9 min

NOTEDo this section only if you used detergent.
  1. Put the detergent tube into a container of clean water.
    • Briggs and Stratton gives a pail of clean water for this step.
    1m
  2. Operate the machine at low pressure to flush the detergent.
    • Briggs and Stratton gives two minutes for its own machines.
    • Use the time in the documentation for your machine.
    2m
  3. Empty the detergent tank.
    <1m
  4. Rinse the detergent tank with clean water.
    • Karcher gives approximately 0.2 litres of fresh water for this step.
    • Karcher then tells you to operate the device for a short time.
    2m

Stop the machine

Estimated 7 min to 17 min

NOTERelease the water pressure before you disconnect a hose.
WARNING

SET THE MACHINE SWITCH TO OFF.
REMOVE THE PLUG FROM THE SOCKET ON AN ELECTRIC MACHINE. Water and electricity together can cause an electric shock.

  1. Set the machine switch to off.
    <1m
  2. If your machine is electric, remove the plug from the socket.
    • Sun Joe tells you to remove the plug before all maintenance work.
    <1m
  3. If your machine has an engine, do the engine storage steps in your documentation.
    • This page gives no engine instruction.
    • The engine has its own storage section in the manufacturer documentation.
    <1m
  4. Close the water supply tap.
    <1m
  5. Point the trigger gun at the ground.
    • Generac tells you to point the spray gun in a safe direction.
    <1m
WARNING

RELEASE THE WATER PRESSURE BEFORE YOU DISCONNECT A HOSE.
Water at high pressure can injure your hand.

  1. Squeeze the trigger to release the water pressure in the hose.
    • Hold the trigger until the water flow stops.
    <1m
  2. Engage the safety lock on the trigger gun.
    <1m
WARNING

LET THE MACHINE COOL BEFORE YOU TOUCH THE ENGINE.
The engine and the exhaust stay hot after use and can burn your skin.

  1. Let the machine cool.
    • Generac tells you to let the unit cool before storage.
    5m

Drain the water from the machine

Estimated 7 min to 11 min

NOTEWater that stays in the machine freezes and damages the pump.
Time that your machine can operate without a water supply
Unverified — do not rely on this value
CONSULT THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE. A LONG OPERATION WITHOUT WATER DAMAGES THE PUMP.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Two registered tier-1 sources give different times for the same operation and the difference is published rather than averaged. The Sun Joe SPX3000 manual gives a few seconds, until the remaining water in the pump exits, and then off immediately. Kärcher's international storage guidance gives approximately half a minute, without a water connection, until the machine has run totally dry. Both makers are describing their own machines, but the gap is large on a component that operating without water can destroy, so no general time is published here. Use the time in the documentation for your own machine, and ask the maker if it gives none.
  1. Disconnect the water supply hose from the inlet adapter.
    <1m
  2. Disconnect the high-pressure hose from the machine.
    <1m
  3. Disconnect the high-pressure hose from the trigger gun.
    <1m
  4. Hold each hose vertical to drain the water.
    • Sun Joe tells you to keep the high-pressure hose straight.
    2m
  5. Drain the water from the trigger gun and from the spray wand.
    • Generac tells you to drain the hoses, the spray gun and the lance.
    <1m
  6. Remove the nozzle from the spray wand.
    • Drain the water from the nozzle.
    • Put the nozzle in its storage position on the machine.
    <1m
NOTICE

USE ONLY THE PUMP DRAIN METHOD IN THE DOCUMENTATION FOR YOUR MACHINE.
Water lubricates the pump. A longer operation damages the pump.

  1. Do the pump drain method in the documentation for your machine.
    • Sun Joe gives a few seconds of operation and then an immediate stop.
    • Karcher gives approximately half a minute for its own machines.
    • Generac gives about six pulls of the recoil handle on an engine machine.
    • The three methods are different. Use the method for your machine.
    1m
  2. Dry the outer surfaces of the machine with a cloth.
    • Generac tells you to wipe the components with a rag.
    2m

Put the pump protector into the pump

Estimated 9 min to 12 min

Quantity of pump protector for your pump
Unverified — do not rely on this value
CONSULT THE DIRECTIONS ON THE CONTAINER AND THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE. NO MAKER IN THE SOURCES FOR THIS PAGE PUBLISHES A QUANTITY.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

WARNING

DO NOT USE ENGINE ANTIFREEZE IN THE PUMP.
Antifreeze for an engine usually has ethylene glycol. ATSDR states that ethylene glycol can cause death.

  1. Read the directions on the container of the pump protector.
    • The directions give the quantity and the method for the product.
    • Karcher gives no directions on the product page for Pump Guard.
    2m
  2. Wear the protective gloves.
    <1m
WARNING

KEEP CHILDREN AND ANIMALS AWAY FROM THE PUMP PROTECTOR.
ATSDR states that ethylene glycol has a sweet taste. A child who drinks it can die.

  1. Keep all children and animals away from the work area.
    <1m
  2. If the directions give a hose method, connect a short hose to the inlet adapter.
    • Generac gives a 3-foot length of garden hose.
    • Briggs and Stratton gives about one yard.
    1m
  3. Pour the quantity of pump protector that the directions give into the hose.
    • No maker in the sources for this page publishes a quantity.
    <1m
  4. If the directions give an aerosol method, put the container nozzle into the inlet adapter.
    • Some pump protectors come in an aerosol container.
    • Use the method that the directions for your product give.
    • Apply the pump protector for the time that the directions give.
    1m
  5. Do the circulation step in the documentation for your machine.
    • Generac gives two pulls of the recoil handle.
    • Briggs and Stratton also gives two pulls of the recoil handle.
    • An electric machine has no recoil handle. Use the method in its documentation.
    • Stop when you see the pump protector at the outlet of the pump.
    2m
  6. Disconnect the short hose from the inlet adapter.
    <1m
  7. Wash your hands after you touch the pump protector.
    <1m
  8. Attach a label to the machine with the date and the name of the fluid.
    • The label tells you what to flush from the pump in the spring.
    2m

Store the machine

Estimated 6 min to 14 min

Lowest temperature that your pump protector accepts
Unverified — do not rely on this value
READ THE RATING FROM THE CONTAINER OF THE PUMP PROTECTOR THAT YOU OWN, AND CONSULT THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Lowest storage temperature that your machine accepts
Unverified — do not rely on this value
CONSULT THE MANUFACTURER DOCUMENTATION FOR YOUR MACHINE. STORE THE MACHINE WHERE WATER DOES NOT FREEZE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Store the machine in a dry area where water does not freeze.
    • Sun Joe tells you to store the machine in a room where water does not freeze.
    • Karcher warns that a garden shed or a garage can become colder than that.
    2m
NOTICE

DO NOT PUT THE MACHINE NEAR A HEAT SOURCE.
Sun Joe warns that heat can dry the seals in the pump.

  1. Do not put the machine near a heat source.
    • Sun Joe warns that heat can dry the seals in the pump.
    <1m
  2. Store the pump protector in its own container away from children and animals.
    • Close the container of the pump protector.
    1m
NOTICE

FLUSH THE PUMP WITH CLEAN WATER BEFORE YOU USE THE MACHINE AGAIN.
Sun Joe warns that antifreeze can damage paintwork.

  1. In the spring, flush the pump with clean water before you use the machine.
    • Sun Joe tells you to flush the machine completely with clear water before use.
    • Read the flush instruction in the documentation for your machine.
    2m
  2. Obey the local rules for disposal of the fluid from the pump.
    • Do not put the fluid into a drain.
    1m

Terminology

This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.

pressure washer pump
Also called: power washer pump, jet wash pump, the pump on my pressure washer, washer pump head, karcher pump
pump protector
Also called: pump saver, pump guard, pump shield, pump antifreeze, pressure washer antifreeze, the pink stuff, pump saver oil, pump lube
winterize
Also called: winterise, winterizing, storing for winter, putting it away for the winter, freeze proofing, frost protection, getting it ready for winter
pressure washer
Also called: power washer, jet washer, jet wash, karcher, power hose
inlet adapter
Also called: water inlet, garden hose connection, hose inlet, the bit the garden hose screws onto, inlet fitting
trigger gun
Also called: spray gun, the handle, wand handle, trigger handle, gun and lance

When to use a professional

Stop if the pump leaks after the winter. Do not open the pump. Do not remove the unloader valve. A split pump housing is not a home repair. Speak to a service dealer for your machine.

Stop if the high-pressure hose, the trigger gun or the spray wand has damage. Do not repair a high-pressure hose. Speak to a service dealer.

Stop if you cannot find the storage section for your machine. Do not use a fluid from a different machine. Do not use engine antifreeze. Speak to the maker of your machine.

This page gives no engine instruction. Read the engine storage section in the documentation for your machine. Speak to a service dealer for engine work.

Speak to the poison control centre in your area immediately if a person swallows antifreeze. Do this also if an animal swallows antifreeze. Do not wait for symptoms. Then get medical aid. Tell the medical staff the name of the fluid.

Speak to an electrician if the socket for an electric machine is wet or has damage. Do not use the machine.

Common questions

Can I just drain it, or do I really have to put something in the pump?

It depends on whose machine you own, and this is the biggest disagreement between the manufacturers we read. Kärcher's international winter guidance is drain-only: clear the residual water, run the cleaner briefly without a water connection, and keep it away from frost — no fluid is mentioned anywhere in it. Sun Joe's SPX3000 manual instead lists running a non-corrosive, non-toxic anti-freeze, a pump saver or a pump protector through the machine before winter. Generac says failure to prepare the pump will permanently damage it and that freeze damage is not covered under warranty. Draining is the part everyone agrees on, so do that first and properly, then read your own storage section for whether a fluid is expected on top.

Can I use RV antifreeze in a pressure washer pump?

Generac says yes for its machines and is specific about which kind: RV antifreeze, alcohol free. Sun Joe's manual permits a non-corrosive, non-toxic anti-freeze without naming a product. Kärcher points the other way and says ordinary anti-freeze is insufficient and not recommended, and sells its own Pump Guard instead. Briggs & Stratton does not use an antifreeze for the pump at all and names its own Pump Saver oil. There is no universal yes here and we are not going to invent one: what is safe for the seals in one pump is not automatically safe for the seals in another.

What is pump saver, and is it the same thing as antifreeze?

No, and conflating them is how people put the wrong thing in. A pump saver is an oil-based product — Briggs & Stratton's is described as pump saver oil, part 6039 — and its job is to coat the pistons and seals so they do not dry out, rust or seize. An antifreeze is a water-miscible fluid whose primary job is to depress the freezing point of whatever water is left behind. Kärcher's Pump Guard and Generac's Pump Shield are proprietary products that claim to do both. Four different chemistries are sold for the same slot, and the only authority on which one your pump tolerates is the company that built it.

Do electric pressure washers need this too, or is it only the gas ones?

Just as much, because the thing that freezes is the pump and an electric machine has a pump like any other. Sun Joe's SPX3000 is electric and its manual carries a full Winterizing and Long-Term Storage section. Generac's storage article has a separate electric section running the same shutdown, drain and pump-protection sequence as the gas one. The one real difference is that an electric machine has no recoil handle, so follow whatever your own manual gives in place of that.

My pressure washer froze and now it leaks. Can it be fixed?

Sometimes, and it is a job for a service dealer rather than a kitchen table. What fails is usually the pump housing or the seals: water expands as it freezes and pushes the components apart from the inside, which is the failure Kärcher describes when it says seals and pump engineering can be destroyed. A cracked housing is often the end of an inexpensive consumer machine, because a replacement pump assembly costs a large fraction of a new unit. Do not run it to see how bad it is, and do not open the pump yourself. Get a dealer quote before you decide, and note that Generac states plainly that freeze damage is not covered under warranty.

How long can I leave a pressure washer sitting before I need to do this?

Generac gives 30 days for its own machines: if the machine will not be used for more than 30 days, prepare the engine and the pump. That is Generac's number and it is true of Generac machines — no other maker we read publishes a threshold at all, so we are not promoting it to a general rule. The more useful trigger for most people is the weather rather than the calendar: if the place you keep the machine can drop below freezing before you next use it, do this job now. The damage happens on the first hard night, not gradually.

Why will this page not just tell me which product to buy?

Because the four manufacturers we registered give four different answers in print, and picking one for you would mean overriding the company that made your pump. Kärcher says ordinary anti-freeze is not recommended; Generac names its own Pump Shield or an alcohol-free RV antifreeze; Briggs & Stratton names a pump saver oil; Sun Joe accepts any non-corrosive, non-toxic option. What goes through a pump is a chemical compatibility question, and this site does not publish a safety-critical value it cannot trace to the maker of the specific machine. The method on this page is the part that holds everywhere; the product is the part that does not.

Do I have to flush it out again in the spring?

Yes, and Sun Joe is unusually direct about why: its manual instructs the owner to completely flush the unit with clear water before reusing it, and warns that anti-freeze products can damage paintwork. There is a second reason nobody prints — whatever you put in the pump ends up on the first surface you clean, which might be a car or a deck. Flush before the first job of the year, not during it. That is why this page has you label the machine with the date and the fluid you used.

Is it safe to use the antifreeze from the garage, the stuff for the car?

No, on two separate grounds. On compatibility, both Kärcher and Generac steer their owners away from ordinary automotive antifreeze — Kärcher says it is insufficient and not recommended, and Generac specifies RV antifreeze, alcohol free. On toxicity, most automotive antifreeze is ethylene glycol, and ATSDR records that it is odourless but sweet-tasting, that large amounts damage the kidneys, nervous system, lungs and heart, and that swallowing a larger amount can cause serious illness or death. A machine stored in a garage with a sweet-tasting spill under it is a bad combination if there is a dog or a small child in the house. Keep the container closed and out of reach, whichever product you use.

Does this page cover storing the engine as well?

No, deliberately. This page is scoped to the pump, because that is the part a single frost destroys and the part whose correct treatment is genuinely disputed between makers. Engine storage is a separate procedure with its own section in your own documentation. Do that section from your own manual, then come back and do the pump.

Sources

Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.

  1. Tier 1Sun Joe SPX3000 Electric Pressure Washer Operator's Manual (MR15, 06272023)Snow Joe, LLC (Sun Joe) · accessed 2026-07-29 · re-verification due 2027-01-25
  2. Tier 1How to prepare your pressure washer for storage (How do I store or winterize my pressure washer?)Generac Power Systems, Inc. · accessed 2026-07-29 · re-verification due 2027-01-25
  3. Tier 1Pump Guard, 9.558-998.0Kärcher North America, Inc. · accessed 2026-07-29 · re-verification due 2027-01-25
  4. Tier 1Making the garden winter-proof: Here's howKärcher (Alfred Kärcher SE & Co. KG) · accessed 2026-07-29 · re-verification due 2027-01-25
  5. Tier 1Winterize & Store Your Pressure WasherBriggs & Stratton, LLC · accessed 2026-07-29 · re-verification due 2027-01-25
  6. Tier 1Ethylene Glycol — ToxFAQsAgency for Toxic Substances and Disease Registry (U.S. Department of Health and Human Services, CDC) · accessed 2026-07-29 · re-verification due 2027-01-25

Revision history

Current version 1 · updated 2026-07-29 · next review due 2027-07-29

  1. v1 · 2026-07-29First draft. The predicted sourcing band tier1-per-unit held: six tier-1 documents were read (Sun Joe SPX3000 manual page 13, Generac's storage article, Kärcher's Pump Guard page, Kärcher's international winter-proofing guidance, Briggs & Stratton's winterize-and-store article, ATSDR's ethylene glycol ToxFAQs) and not one publishes a value true of any machine but its own, so all six specifications publish as consult-manufacturer instructions with no digit in them. Two conflict_note fields publish disagreements unreconciled: the pump protector fluid, and the time a machine may operate without a water supply. Per-maker figures are attributed by maker in substeps and the FAQ and never promoted to verified specifications. ATSDR backs two hazard levels only. Scoped to the pump; engine storage is routed to the reader's own documentation.

Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.

Comments and corrections

Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.

Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.

The comment system is not connected yet. Comments are stored in GitHub Discussions through Giscus, outside this site, so that a redeploy cannot destroy them.