Engine coolant…

This is a post I penned in 2010...but it's still relevant and interesting...I think... :-)

Coolant, antifreeze, water, radiator fluid…whatever you call it – it still the same thing!  The coolant system is a system that is not just used in the engine, but in parts of the rest of the car too.  Engine coolant is typically a combination of water and ethylene glycol.  Water has a freezing temperature of 0 degrees Celsius/32 degrees Farenheit, but adding the ethylene glycol actually lowers the point at which it freezes. Antifreeze typically refers to the ethylene glycol.

So what exactly does it do?  It takes the heat of the engine (which is fire encased in a metal box) and transfers it to the air.  The coolant system usually contains passages throughout the engine, a thermostat, a radiator and a degas-ing bottle.

Sidenote:  The first time I saw the word “degas” I was pronouncing it like Vegas, but with a “d”.  It made so much more sense when I realized how it was usually pronounced – dee-gas

The thermostat allows the coolant in the engine to flow to the radiator.  The thermostat opens and closes depending on the temperature of the engine coolant.   The radiator cools the coolant with the air.  Although it may be a hot day, the air is still going to be cooler than the coolant!  Unless you’re on Mars Mercury…

In addition to the thermostat, radiator and coolant through the engine, the other necessary component is the degas bottle.  (Rolling the dice on coolant?!?!)  The degas bottle does exactly what it is called – it removes the air from the coolant system.  It does this by leaving a gap of air in the bottle, which absorbs any of the bubbles that might be in the coolant.  Because of the degas bottles purpose – which is usually the container that you would pour coolant into – you never want to have coolant to the brim of this bottle.

A few sites to check out:
How Does Anti-freeze Work?
Video: How Does an Engine Coolant System Work