Cooling system: Difference between revisions

 
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[[image:RADIATOR.png|100px]]
[[image:RADIATOR.png|100px]]


The thermostat feels the temperature of the engine and decides how much cool water flow it should be fed with, in order to keep that temperature stable. The thermostat is basically a one-way valve that keeps the coolant inside the engine and doesn't allow it to circulate through the radiator while the engine is warming up. This means that the radiator isn't cooling the coolant when it isn't necessary to do so, which helps bring the engine up to proper operating temperature more quickly. As the engine temperature rises, the thermostat opens gradually, until it is fully open when the engine is warmed up. This lets all the coolant pass into the radiator to cool and then cycle back into the engine.  
The thermostat feels the temperature of the engine and decides how much cool water it should be fed with, in order to keep the engine temp stable. The thermostat keeps a minimum flow of water into the radiator while the engine warms up. This helps bring the engine up to proper operating temperature more quickly. (That's a good thing.)
 
After the engine reaches the proper temperature of operation, the thermostat opens gradually, but only enough to keep that temperature in the engine constant, avoiding over-cooling.
If the cooling of the water in the radiator is not enough, even when the thermostat is fully open, then the electric fan starts.


This schematic shows the components of the Ninja 250 cooling system and how they relate to each other.  
This schematic shows the components of the Ninja 250 cooling system and how they relate to each other.  
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Now, imagine you get off the freeway and pull up to a stoplight.  Your heat/water tank is full, because you've been generating a lot of heat driving fast.  The cooling system was able to drain off enough heat to keep things under control as long as you were moving, but the tank filled up in the mean time.  Now that you're stopped, the air flowing over the radiator is reduced to zero (which means your drain pump is down to zero pumping power).  Suddenly, any excess heat at all (such as running the engine at idle) is enough to overflow the tank, because it's so full.  The temperature gauge shoots up until the fan kicks in -- there's the drain pump stepping in at the last minute before the tank overflows.  This situation (before the fan kicks in) is shown in the third diagram.
Now, imagine you get off the freeway and pull up to a stoplight.  Your heat/water tank is full, because you've been generating a lot of heat driving fast.  The cooling system was able to drain off enough heat to keep things under control as long as you were moving, but the tank filled up in the mean time.  Now that you're stopped, the air flowing over the radiator is reduced to zero (which means your drain pump is down to zero pumping power).  Suddenly, any excess heat at all (such as running the engine at idle) is enough to overflow the tank, because it's so full.  The temperature gauge shoots up until the fan kicks in -- there's the drain pump stepping in at the last minute before the tank overflows.  This situation (before the fan kicks in) is shown in the third diagram.
==More info==
For a little extra reading on the cooling system, we suggest the following:
http://www.stewartcomponents.com/tech_tips/Tech_Tips_6.htm
http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capability_in_high-performance_automobiles.htm
http://www.engineeringtoolbox.com/pumps-discharge-regulation-d_310.html
http://www.arrowheadradiator.com/Radiator_Diagnosis,_%20Repair,_%20&_%20Replacement_%20Tips.htm
http://www.arrowheadradiator.com/overheating_causes_and_cures.htm
http://www.familycar.com/Classroom/CoolingSystem.htm