Dyes are used in heavy-duty coolant and light-duty automotive coolants in order to add a distinctive colour to the product.

They have no impact on the performance of the coolant. If no dye were added, the colour of the coolant would look very similar to water.

This would make leaks difficult to detect and could lead to safety issues in the workshop if coolant was mistaken for water.

In the past, the industry nearly landed on a colour consensus for coolant, with blues, greens and yellows being mostly used for conventional coolants, while orange/red products were reserved for long-life OAT coolants.

However, as OEMs and coolant suppliers upgraded their products they ether adopted or continued to apply their own tiered product approach to differentiate their own products, or to match the colour of existing competitor products. No matter what the technology type, no rules seem to apply.

At Cummins Filtration, the team working the FleetguardMAP laboratory receives and analyse field samples returned from customers as well as new products available in market from OEMs and coolant suppliers.

A recent report finds that there is minimal alignment of coolant technology type and colour. Just looking at a coolant’s colour, the team couldn’t say if it was the same or different in any way to another.

For users, this means if they don’t confidently know what coolant is being used in their equipment, then they shouldn’t simply lift the bonnet and be confident in topping up their cooling system with any coolant of the same colour.

The coolant could be completely different to what the vehicle needs and cause of future cooling system issues.

So, the message from the team at Cummins Filtration is simple: Do not pick a coolant by its colour!

The colour is only there to help your mechanic spot a potential leak. If you choose your coolant based on its colour, it’s a sure way to cost you time and money.

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