Coolant ≠ airless storage fluid: do not rely on colour

…same colour, different chemistry

Customer question
« Hello everyone, I wanted to know if, for winter storage, we can replace the pump armour with coolant? »

Short answer: No, it’s not a good idea. Even though both liquids may be blue in colour, they do not have the same chemical composition or function. Airless manufacturers recommend using dedicated storage fluids to prevent corrosion, valve seizure and difficult starts in spring. Graco states in black and white: “Never leave water in the pump… For storage, flush with Graco Pump Armor…” and specifies that storage without Pump Armor causes problems when restarting.

1) What these liquids (really) contain

Airless storage liquids

• Graco Pump Armor: blue liquid formulated to protect against corrosion and facilitate restarting. Its safety data sheet (SDS) shows an ethylene glycol base (40–60%) plus sodium nitrite (0.1–1%) as a corrosion inhibitor (hazard H302 “harmful if swallowed”).
  Graco summarises its use as follows: “Pump Armor prevents corrosion and ensures easy starting.”

• Wagner EasyClean (Titan LS-10): aqueous mixture designed for cleaning and protection, to be diluted 1:30 in water. The SDS lists ethanol (15–40%), water (15–40%), glycerol (5–15%), 1,2-propanediol = propylene glycol (5–15%) and dipotassium phosphate (1–5%).

Automotive coolant

Engine coolants are heat transfer fluids for automotive circuits operating at ~90°C, mainly based on ethylene glycol or propylene glycol + a package of inhibitors that varies depending on the technology: IAT (inorganic based on silicates/phosphates), OAT (organic acids), HOAT (hybrid, e.g. Si-OAT). E.g. BASF Glysantin G40 (Si-OAT): ethylene glycol + organic inhibitors and silicates.

Important: the colour of coolant is not standardised and cannot be used to identify its chemical composition. The AAA explicitly states: “Do not use colour to identify the type of fluid.”

2) Why substitution « coolant auto » → « pump armor » pose a problem

1. Different objective

   • Airless : protect pump parts (body, balls/seats, seals), prevent corrosion, deposits and valve sticking, ensure immediate priming after storage.

   • Automotive: transfer heat during hot operation, protect engine metals (aluminium, cast iron, brass, etc.) during years of service.

2. Unsuitable additives

   • Silicates/phosphates (depending on the coolant family) form films/minerals that are useful in engine circuits but undesirable in the narrow passages of an airless pump (seats/valves/bypasses) where they can leave deposits and promote sticking. (Principle documented on the engine side: silicates are abrasive and can wear out seals/water boxes; when applied to an airless pump, these solids/films should be avoided.)

3. Material / paint compatibility

   • OAT/HOAT coolants use organic acids and various azoles/buffers designed for engine alloys. Their behaviour on the elastomers and technical leathers of airless seals (or with regard to paint/water residues) is not guaranteed. Airless storage fluids, on the other hand, are formulated to remain paint-friendly and can be easily rinsed with water before reuse.

4. Toxicity / safety

   • Many coolants contain concentrated ethylene glycol (toxic if ingested). Pump Armor also contains this substance, which is why it is important to follow the dedicated procedure (collection, labelling, secure storage) and avoid improvised substitutes that are not documented by airless manufacturers.

5. Manufacturer recommendations

   • Graco: “Never leave water in the pump… For storage, flush with Pump Armor or white spirit/thinner”; “Storage without Pump Armor will cause problems when restarting”. These are official instructions… not options.

 

3) Summary table

4) Best practices for storage (winter or long breaks)

1. Never leave water in the appliance (risk of corrosion/freezing).

2. Clean according to the type of paint used (water-based or solvent-based).

3. Circulate a dedicated storage fluid:

   • Graco Pump Armor (ready to use).

   • Wagner EasyClean : Dilute 1:30 in water before circulation.

   • Farbmax : Dilute 1:30 in water before circulation.

4. Release the pressure, close the relief valve, leave the fluid in the circuit during storage (follow the instructions for your machine).

5. Store in a frost-free location whenever possible; if this is not possible, check the antifreeze protection of the fluid used. (EasyClean is diluted, Pump Armor is an antifreeze; refer to the instructions for use.)

🔒 Safety: Handle products according to the safety data sheet (SDS). Label and store out of reach of children/animals.

 

5) “But it’s the same colour…” — why it’s tricky

Colour is not a specification. A blue coolant will not have the same composition as another blue coolant; the same applies to airless fluids. The AAA is categorical: you cannot determine a type of coolant by its colour, as each manufacturer colours its products as it sees fit. Apply the same principle to airless fluids: rely on the instructions, not the colour.

6) Clear (and economical) recommendations

If you are looking for the safest solution for your airless sprayers without breaking the bank, stick to products designed for these machines:

• FARBMAX maintenance fluid – 1 litre: protects against corrosion, damage and freezing; mix 30:1 (water:product); designed to be sucked up and left in the appliance during storage.

• FARBMAX set – 3 × 1 L: same use, more economical packaging if you maintain several machines or carry out repeated winter storage.

Furthermore, if you are working with Wagner, EasyClean at 1:30 works very well for short/medium-term preservation.

💡 Budget tip: if you maintain your machines regularly, the 3 × 1 L pack is often the most cost-effective choice over the course of a year.

7) FAQ express

Can we use “motorhome antifreeze (PG)”?
Some people do this, but airless manufacturers do not recommend it. You lose the guarantees of a formula designed for pumps (easy rinsing, additives suitable for valves/seals, documented procedures). Follow your manual: Pump Armor (Graco), EasyClean (Wagner) or Farbmax are the benchmarks.

Pump Armor also contains ethylene glycol: how does it differ from automotive coolant?
The function and additive package make all the difference: Pump Armor is calibrated to protect airless hydraulics (anti-corrosion nitrite, viscosity/water content suitable for flushing, pressurisation/depressurisation procedure) and is recommended by the manufacturer.

How long can the storage fluid be left in the machine?
Throughout the winter period. Follow the instructions for your machine when restarting it (rinsing, draining, pressure testing).

Should I dilute the fluid?
They are all ready to use and provide optimal protection for airless and aircoat machines. However, for frequent storage, these products can be diluted (e.g. 1:30) in order to save a little each year. Check the label of the product used.

Key points to remember

• Do not replace airless storage fluid with automotive coolant, even if the colour appears to be the same.

• Follow the manufacturer’s procedures (Pump Armor / EasyClean / Farbmax, rinsing, pressure, frost-free storage).

• For low cost and maximum peace of mind, opt for dedicated maintenance:
  FARBMAX 1 L and FARBMAX 3×1 L.

Other articles that may interest you

• Guide : How to clean an airless pump after use
• Tutorial : Winterising a Graco/Wagner step by step
• Advice : The 5 biggest mistakes in airless spraying
• Recommendations : How often should I clean my airless device

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For any further questions or if you would like to get your hands on one of these products seen in this article, you can contact us on +49 (0) 30 220 15436, fill out our contact form or email us. If you wish to purchase one of the products mentioned above, you can check them out in our online store. You can also visit us at our service base during office hours.