Test all limits in the Nissan Navara
Test all limits in the Nissan Navara

Radiator failure – here’s why

Adding coolant to your radiator

“Can I check your oil and water?”

A common question heard at many service stations; but don’t be fooled − that little top-up could be doing your vehicle’s engine more harm than good.

It’s been said that at least 33% of all vehicle breakdowns are cooling-system related. While this statistic may vary from region to region, it’s certainly believable in countries where summer temperatures soar above the 30ºC mark.

So, why are so many people steaming to a stop? The answer is simple: poor-quality coolant.

Corrosion is the leading cause of radiator failure, both internally and externally. External corrosion is usually the result of salty sea air rotting the cooling veins of the radiator, while internal corrosion can be caused by several factors, the most common of which is topping up your radiator with plain water, and not adding engine coolant to the mix.

Generally speaking, your engine’s anti-freeze/water ratio should be approximately 40:60 respectively. If you’re adding small amounts of water every week, the chances are good that your cooling system is in need of repair.

More importantly, every time you add water to your radiator without adding anti-freeze, you’re effectively diluting the coolant, and it’s only a matter of time before corrosion sets in.

Rust particles are highly abrasive; if your coolant is a dirty brown colour it means that your system’s internals are being worn away, and that may include your engine’s water pump.

Another major contributor to internal corrosion is improper earthing. If your engine is incorrectly earthed, the coolant within your system can act as an electricity conductor, turning your entire system into a fast-acting corrosion experiment.

Typically speaking, your engine’s cooling system should be flushed every 18 months; this should include replacing the coolant with a good quality anti-freeze at the specified mixture ratio.


Most of us are aware of our engine’s lubrication needs – particularly when it comes to oil changes and the use of a good quality lubricant – but how many of us can say we pay the same degree of attention to our engine’s coolant needs?

That said, here are several do’s and don’ts regarding your engine’s cooling system:


  • Keep a record of all your maintenance work
  • Flush and replace your coolant every 18 months
  • Use only good quality anti-freeze
  • Ensure that your anti-freeze to water ratio is 40:60
  • Ensure that your belts are correctly tensioned – too loose can cause slippage, and too tight can damage your water pump’s bearing
  • Check the condition of your hoses and belts regularly – if your radiator pipes feel stiff when you squeeze them, they could have rust built up on their inner walls
  • Regularly rinse your radiator with a hosepipe, removing all grass seeds and bugs from the core
  • Monitor your temperature gauge at all times
  • Travel with extra anti-freeze in your boot
  • Buy a spare thermostat and radiator cap – and keep them in your vehicle at all times.


  • Continue to drive if your vehicle starts to overheat
  • Fit any other thermostat to your vehicle other than the one specified by the manufacturer
  • Restrict airflow to your radiator
  • Rely solely on garage attendants to monitor your vehicle’s coolant levels

Compiled by Q20 Lubricants and first published on www.4x4equipt.com

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