What coolant do I top my Car up with

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Coolant types and what to do next

This is a universal question as any engine will use some form of coolant but it becomes confusing to the end user or vehicle owner.

The first question I ask is how do you inspect the cooling system ?
Not a trick qustion
Some believe by checking the bottle of coolant on the side or connected to the radiator, also known as the recovery bottle.

The purpose and design of the recovery bottle is to store expanded hot water or coolant when the engine is hot, then as the engine is cooling down over night the water/Coolant returns to the cooling system to prevent any air pockets, thus causing any rapid heating and or rapid cooling.

Here is where the problem or misunderstand begins.
If we just check the recovery bottle this is good so long as we only checking levels and that they stay in the range between LOW and HIGH.

Where we need to be concerned if the coolant level disappears below the low level, this is the first sign of something going wrong.

At this stage don’t panic

Let me stop at this point as there are levels of Cooling system failures
A minor level of concern is a leaking hose, faulty radiator, faulty thermostat, blocked radiator, or a cracked recovery bottle and or poorly connected tube from radiator to the recovery bottle.

A major level of concern is a leaking head gasket, but we must be 100 % sure that our diagnosis is correct, as a blocked radiator or a faulty thermostat may lead you in the wrong direction.

Then of cause we need to establish the cost per benefit analysis, that is, if we have a leaking head gasket and the vehicle is 20 years old or there are other things going wrong at the same time then we need to compare the cost of the repair to the vehicle value.

Keep in mind that on a older type of vehicle there are less guarantees that the repair will be successful as the engine may have exceeded the heat range if driven when overheated.

If an engine is operated when overheated the rings will loose there elasticity with a result of a smokey engine or longterm damage.

Now back to the coolant, if the vehicle is under five years old and under 100,00 kms, stick with the coolant that is in the engine.

Easier said than done as you may not know from where the vehicle was serviced and when.

My rule of thumb if I needed to change the coolant firstly I would measure the coolant concentration by checking the cooling in the radiator not in the recovery bottle and if the coolant concentrate is less than 20% then yes go ahead and consider to add coolant.

Caution is required, when opening a radiator cap is dangerous when hot so never remove the radiator cap when the engine is hot.

Caution No2, never fill a radiator when the engine is hot, as this may cause rapid cooling to the head, that may lead to a damaged head or a cracked head.

If you need to fill the radiator when the engine is hot, then this is what you need to do;

Start the engine with the radiator cap already opened and pour the water in with the engine running at idle speed only, this procedure will allow water into the radiator without causing any potential head damage.

You may be asking how is this possible, it’s because the water pump will draw the water from the lower part of the radiator into the engine up to the thermostat, by this time the water will be at a high enough temperature not to cause damage to the head.

When shopping for coolant it’s very easy to get confused, by price and information, as anybody and everybody makes a coolant product, so here is a guide.

Lets say we a changing the coolant in our engine because the glycol concentration is below 20% and the car is over 5 years old, and done about 110,00 kms.

to be continued





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