• Team Vebo

Un”Coolant” Story


Our coolant story is inspired by a recent question from a customer, “Can I replace my coolant with tap water?”. Our answer for this is; If you love you car, No!

Before we discuss about the technical bits about coolant, let’s ask ourselves when was the last time we checked our car’s coolant level? Most of us here in Malaysia would probably forget about coolants until something catastrophic happens, like our car gets overheated due to low or even empty coolants. So this chapter we would like to disclose an un“coolant” truth behind.


Just to illustrate how bad erosion can happen due to improper coolant usage, have a look at the pictures below. The first photo shows a water pump that is badly corroded. The second image is a brand-new water pump. Big difference huh?



Corroded Water Pump Fins

New Water Pump




Minerals in tap water will build up over time and clog the passageway. This will further lead to build up of pressure within the hose system. The pressure will eventually rupture the radiator top cover or even the radiator fin.



Broken Radiator

Corroded water can also run through the engine which will cause complication.



Engine With Corroded Water

So how often do we change coolant?


Most car manufacturers recommends once every 50000KM.



Which coolant should we use?


There are three main types of coolant that car companies use: Inorganic Additive Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT).


Typically, older cars use IAT. It needs to be changed every two years or 38,000 KM, making it far inferior to newer formulas. One of those newer formulas is OAT.


Vehicles use this formula and normally require a change after five years or 80,000 KM. Finally, HOAT is a derivation of OAT that requires the same time change interval unless otherwise specified.-+


Depending on your car, you may or may not need to use coolant in your radiator. Consult your operation manual for details. Always use distilled water instead of tap water to avoid complication.



When you’re replacing your coolant, you would need to bleed the air out of the cooling system in your car. Air pockets — or hot spots — are dangerous; they can overheat, crack or warp any part of the engine where the air is trapped.

Usually, replacing the coolant or servicing the cooling system in your vehicle can lead to hot spots in the system. Air may also enter the system through the coolant reservoir from time to time on some vehicle models.


A hot spot is nothing more than trapped pockets of air or bubbles inside cooling system passages that prevent coolant from carrying heat away from those areas, causing the engine to overheat and corrosion to start setting in.


If you’ve just replaced your coolant and fixed your cooling system, run a test before going for long drive. This can be done by running the engine until the fan starts to spin. Always check your coolant and water level before a long drive.

If there are coolant replacement or top up due to leak, it is advice to run the pressure tests on the entire coolant system with 1 Bar of pressure. These tests are important to ensure there is no more leak after the hoses been removed during the coolant replacement. Test example below:

Pressure Test


As a conclusion, the cooling system is vital for the longevity of your engine. Take time to periodically check your coolant level and replace your coolant based on manufacturer's recommendation.

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