Have you been noticing your temperature gauge jumping around lately? How about your engine not warming up soon enough after you've started it? Or worse, is constant overheating a problem? If you are noticing a problem regulating your engine's operating temperature but can't find a coolant leak, then you may want to look at your coolant thermostat. The last thing you want from such a simple and cheap part is for it to cause a complicated and expensive problem. Any time coolant temperatures are not kept regular, sealing systems and moving internal parts are subject to failure. If your engine isn't warming up fast enough, then the thermostat may be stuck open and you will suffer increased emissions and a slight lack of power until the engine heats up. Your passenger compartment will also not heat as well. If your engine is running too hot, it may be because the thermostat is closed and the coolant is bypassing the radiator. Either way, fixing much more expensive parts on your car can easily be the result of not replacing a very simple little coolant thermostat.
Right around the time of WWII, liquid-cooled internal combustion engines were becoming increasingly popular due to the efficiency of that system. Obviously the most crucial parts of this system are the radiator and water pump. They work in unison to cycle and cool the liquid that runs through the engine. But the coolant thermostat decides if the liquid coolant is too hot and directs it through the radiator, or if it is too cold and bypasses the radiator. It uses a very simple technology called wax-pellet (or solid-liquid) transition, where the wax inside the thermostat fluctuates between varying degrees of solidity and liquidity depending on the coolant temperature (http://en.wikipedia.org/wiki/Wax_thermostatic_element). This change in state also means a change in the density of the material, and that operates a valve that will govern the amount of flow into the radiator. A properly functioning thermostat is constantly moving between open and closed in order to maintain an optimum temperature for your engine.
If your coolant thermostat is stuck in either the open or closed position, then chances are the valve or spring is broken. You should definitely get it replaced as soon as possible, because constant overheating or overcooling can be detrimental to an engine. On older cars, replacing your thermostat is a very easy job because they are typically located at the top of the engine by the water pump or intake manifold. On newer engines it could be located anywhere, and gaining access could be the most difficult part of the process. But once you know where the thermostat is, you can start the replacement process by first disconnecting cooling hoses that lead to it. This may result in some coolant spilling, so be prepared to clean it up and top off when you are done (in rare instances a coolant drain and flush may be required). Remove the housing or cover that encloses it, making sure to remove all gaskets at this time. Finally, replace your thermostat and gasket (if necessary) following the steps in reverse.
Not all coolant thermostats are created equal; in fact, some high performance engines can have very complicated ones. But that doesn't mean buying one has to be a complicated procedure. At Car Parts Discount, we carry new replacement thermostats from all the top brands and manufacturers. So if you just need an inexpensive one or your car requires the original equipment, we have the quality part for you at a great price. Don't delay, buy it now.