Tech Talk

Proactive coolant testing can save you money

To maintain our health, we might regularly visit the doctor for a blood test to assist in the diagnosis of a health condition. Coolant is akin to our blood, so regularly testing and monitoring the coolant can tell us much about the condition of the cooling system and if anything is wrong that might lead to significant engine health problems.

Every good cooling system maintenance program should include regular coolant testing to determine if the proper level of protection is present or if contaminants exist. A good coolant testing program eliminates guesswork and allows the cooling system to maintain peak performance.

What can easily be tested on-site?

Firstly, what is in our coolant? Fleetguard PGPlus and PG Platinum contain ~45-47 per cent propylene glycol, a few per cent additives/inhibitors/antifoam/dye and the remainder ~50 per cent de-mineralised water. The glycol provides for the antiboil/anti-freeze, the additives/inhibitors provide the corrosion, scale and liner cavitation, the water helps to retain these properties and assist heat transfer. 

The first-up assessment of any coolant is its appearance: Clarity, colour, presence of sediments, suspended matter (cloudiness), presence of oil/fuel on the surface and petroleum, sulphurous or ammonia odours. If it is not typical of new coolant, then there might be a problem. 

In on-site situations when your equipment is in for service, the coolant properties to test are: Glycol content percentage, pH, nitrite and molybdate which relate directly to the coolant, and contaminants such as sulphate and chloride. Fleetguard has a range of products that can be used for testing.

When testing, if the glycol content is lower it generally means the coolant (glycol and additives/inhibitors) has been diluted with water which means less antiboil/antifreeze protection and less effective corrosion, scale and liner cavitation protection. Cummins requires the glycol content to be maintained between 40-60 per cent by volume. Fleetguard sells both PGPlus and PG Platinum as a ready-made premix (~50 per cent vol) in demineralised water. When a coolant is new the glycol concentration, pH and the additives are present at the correct levels. 

Coolant that has been in service for a long period, suffered overheating events or exhaust blow-by (exhaust leak into the cooling system) may suffer a reduction in its pH (chemical stability). Sulphate (from exhaust or source water) and chloride (source water) are typical contaminants that can be detected with Fleetguard test strips.

To assist with on-site testing, Cummins Filtration has a range of coolant test strips and refractometers that can be used on-site as a quick guide to assess the immediate health of your Fleetguard coolant and cooling system condition. 

For more information, visit or call Cummins Filtration on 1800 032 037.

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