The most common operating temperature control device in automobile engines today is the double-valve wax thermostatic element thermostat, but it would be useless without a durable thermostat housing. Since the flow of coolant through your engine changes direction from time to time, it is necessary to have a physical compartment with all the appropriate pathways and bypass tubes that aid in the efficient transfer of said coolant to where it needs to go. If the thermostat housing gets cracked or develops a leak, you will leak coolant all over your engine. This can cause corrosion of valuable engine parts, and you will be forced to continuously top off your coolant levels just so your engine doesn't overheat. It would make much more sense to simply replace your thermostat housing with a new one and save all the hassle and worry about associated with causing severe damage to your engine. After all, this is a much easier fix than a head gasket.
Liquid cooling became most popular on cars after WWII. Rather than relying on a constant stream of air to cool the engine (which does not work while the car is idle), it is more effective to maintain a continuously circulating supply of fluid that travels through the engine absorbing heat and dissipating it through the engine's radiator. This requires a bevy of additional parts be added to the engine, but the engine will be capable of making more power in return. And central to this system is a control device called the thermostat. It reacts to the temperature of the coolant as it travels through the thermostat housing. At times when the coolant is cold enough to absorb more engine heat, the passage to the radiator is blocked so the fluid can continue traveling through the engine. When the coolant heats up, that passage is opened and the coolant now goes through the radiator so the heat can be released rather than bypassing it. And all this is accomplished through a simple thermostat housing.
Thermostat housings can be made of either a durable plastic or a hard metal like steel, iron, or aluminum. Old ones were simply called "water necks", because they just sat at the top of the intake manifold, covered the thermostat, and had a big outlet at the top of it where coolant would travel to the radiator when the thermostat was open. When it was closed, the coolant would simply continue to circulate through the engine. Now, these thermostat housings can be found in a number of different locations; though almost always near the water pump. There are multiple ports that send the coolant to different locations, an air pressure bleeder, and often house a sensor that monitors the coolant temperature so the cooling fan can turn on. Either way, they are not hard to replace, and are essentially simple bolt-on devices. Just remember that your coolant will likely leak when you remove the hoses from the housing... so bring a pan to collect it.
Whether your car is new or old, the parts you use to fix it should be the best around. Car Parts Discount sells nothing be the best replacement thermostat housings and other cooling components for your engine. We promise that the parts you get on our website will fit and function correctly the first time, and that you'll be so happy with our low prices and fast shipping that once you buy from CPD you'll never want to go anywhere else.