If the bloke servicing your plumbing said “we strongly recommend changing your septic filter” you would unconditionally agree, shake the mans hand (after he has serviced you properties poo system) and pay the man what he asked for. You would have zero clue as to what he is talking about, except it has the word septic in it and thats sounds serious. Truth be told, I know very little of plumbing and suspect most people don’t need a septic filter or what it even does. Maybe it makes our urine drinkable.
Yet when your mechanic advises that its time to replace your coolant, people are unsure. Do I need that? Is that an unnecessary up sell? Is a coolant change really comparable to some unknown poo filter the plumber is advising?
Truth be told most vehicles are not getting the coolant replaced in them nearly as often as they should. First let’s address why its needed.
Uncle Bob says coolant is a waste of time and to just put water in the radiator. Good old uncle Bob knows best, after all he built his own house, gave himself asbestoses poisoning, accidentally shot a hole in his own roof, drowns unwanted kittens and picks up women with bigger moustaches than he. How could uncle Bob possibly be wrong?
Well Bob lovers, lets break it down.
Running just water is about as foolish as Trumps Public Relations Manager. Water in any environment involving metal encourages rust. Just in case any of the home viewers were unaware rust in your cooling system is a bad thing. Rust blocks up very small galleries and tends to chew through metal at the same rate Rolf Harris accumulates accusations of indecency. Holes in some things are pleasurable, holes in your cooling system are not one of these things.
Thus tap water on its own is a stupid idea Bob.
Coolant contains Ethylene Glycole which is colourless, and odourless but very sweet. Animals are drawn to it and small children like the taste too. It is highly poisonous if consumed and gives primary symptoms of being very drunk (picking up women with thick Russian moustaches are an early sign of consumption).
Immediate medical attention is required if consumed as it causes kidney failure and in extreme cases brain damage.
Do Not Drink Coolant, even as a joke (somehow Australian society feels the sentence “it was just a joke” justifies prehistoric thought processes).
Manufacturers deliberately add dye to the coolant to avoid it being confused with water and accidentally consumed. As such there is little to no difference between, red, green, blue and orange coolants. However these can not be mixed but we will get to that later.
So why does it need to be replaced? The Ethylene Glycole (along with a few other byproducts and chemicals that will probably give technicians severe and debilitating illnesses later in life) are mixed with water to give your vehicle the perfect mix to allow the boiling point and the freezing point of the liquid a fighting chance when it enters the arena that is your engine.
Drive to Thredbo and leave you car over night and the water drops to below freezing. If the liquid in you cooling system freezes, it expands and your cars cooling system opens up like prom queen on the night of.
Drive home from Thredbo trying to beat the long weekend traffic by revving the living daylights out of your car and the cooling system is now beyond boiling.
Coolant reduces the temperature your water freezes at and it increases the temperature it boils at, it also contains rust inhibitors to stop uncle Bob desecrating your radiator with his water only theory.
Over time the Ethylene Glycole breaks down and loses its ability to do its job and it needs to be replaced.
Regardless of kilometres you should do this every two years.
Never mix coolants. A complete flush is required. Note here a flush is not pulling the radiator hose off in your cousins front yard one Saturday morning and killing his front lawn. The entire system needs to be flushed, the heater core, the block and the radiator.
Once this is done, you can put whatever coolant you like in the car as long as you follow the ratio of coolant to water the product dictates.