Why you should not remove your car’s thermostat
The thermostat is a valve that controls the flow of coolant from the engine to the radiator and vice versa. In most cases, the thermostat is controlled mechanically using a preset motor temperature, but there are few models that use an electrical signal to open and close the gate via a control unit.
When you start the engine (for example in the morning), the engine temperature at that time is cold, so the thermostat is activated. The cold thermostat closes completely, restricting the flow of coolant in the engine and causing the engine temperature to rise sharply.
When the set temperature is reached, the bellows in the thermostat expand and open the shutoff valve, allowing hot coolant to flow from the engine side to the radiator and the already cold coolant in the radiator to flow towards the engine. A thermal switch on top of the engine block detects high temperatures and activates the radiator fan to cool the coolant in the radiator just before the exchange takes place.
When hot coolant enters the radiator, it means that the cold coolant in the engine needs to be exchanged. At this point, the thermal switch continues to send a signal to the radiator fan until all the cold coolant has been absorbed from the radiator in the engine block.
When the block becomes saturated with cold coolant, the fan stops, leaving the hot coolant in the radiator to be cooled by turbulent air while the vehicle is running. The thermostat continues to open and close in sequence in parallel with the thermal switch for as long as the vehicle is running. In the past, there have been misconceptions that have led car owners astray.
In the past, a group of people, both unsuspecting mechanics and non-suspects, have misled vehicle owners into believing that African, particularly East African, vehicles do not require thermostats for normal operation.
They think that thermostats are only meant for tropical regions with freezing cold weather. When a vehicle is imported, they immediately advise the owner to remove the thermostat as it can cause overheating.
If you drive with a thermostat for years, you will be told to remove it immediately whenever the thermostat overheats. To their surprise, the vehicle still responded well for some time after the thermostat was removed, seemingly confirming their theory that thermostats are not suitable for the tropics.
You may wonder why new cars made specifically for the Kenyan market are delivered to car dealerships with thermostats, even though the manufacturers know from the start that it is for the Kenyan market.
If the thermostat was useless, it would have been made without one. The thermostat controls the cooling system and should be part of the cooling system. To understand why you should not remove the thermostat in your car, you must first understand the benefits of having a thermostat on your engine.
Faster warm-up time
Modern cars operate at specified temperatures. The faster this temperature is reached, the more favorable it is for the proper operation of the car. A closed cooling system reduces warm-up times.
The interior heating uses the temperature of the engine coolant. Due to the lack of a thermostat, the vehicle’s occupants cannot enjoy the warmth of the interior heater, especially in cold weather. High fuel consumption: The engine temperature determines the amount of fuel injected into the combustion chamber. When the engine is cold, the control unit injects more fuel to bring the engine to its optimal operating temperature as quickly as possible.
Without a thermostat, the engine is unable to reach its optimal temperature. Because of this, the control unit always assumes that the car is in cold start mode, which causes the car to consume more fuel while it is running, resulting in lower fuel economy. This is the main reason why all vehicles without a thermostat use more fuel.
Mud formation
The optimal operating temperature of an engine is usually between 80°C and 97°C. If the engine operates without a thermostat, the average temperature will be below 50°C. As mentioned before, too much fuel is sprayed or the temperature is extremely low, which causes evaporation in the combustion chamber, which allows moisture to penetrate the cylinder walls and mix with the lubricating oil, resulting in sludge.
At the same time, high humidity has an abrasive effect, causing engine parts to wear out much faster. So why did my car stop overheating and start running normally again after I removed the thermostat? The main cause of this misconception is incorrect diagnosis. Overheating can have many different causes.
From a faulty radiator cap to a warped cylinder head. When an engine overheats, whether the thermostat is the problem or not, if the engine is equipped with a thermostat, it takes a very short time for the pressure to build up and the temperature to rise.
Removing the thermostat will slow down the overheating process. It is easy to get the illusion that the thermostat is the problem and overlook many other aspects.
In some cases, the thermostat may get stuck in the closed position. In this case, it must be immediately replaced with a new one that matches the original grade. A one degree change can stop your engine from functioning properly.
Testing for a faulty thermostat
Before jumping to conclusions and criticizing your thermostat, test it for accuracy first. The steps are simple, but they require concentration. All you need is clean water, a container, a heater, and a thermometer.
– Remove the thermostat from the car, mark and record the degrees graduated on it.
– Gently put the thermostat in the jar.
– Boil the water using the heater as you monitor the temperature using the thermometer.
The thermostat’s gate valve should start to open once the water temperature hits the graduated number. (ie if the graduation on the thermostat reads 76°C, means at 76° gate valve should start to open)
Should the gate valve stay closed 2 degrees past the graduation on the thermostat (i.e graduation says 76 degrees and we are at 78 degrees) abort the exercise and replace the thermostat with a new one.
If the thermostat responds well as graduated on it then it means the cause of overheat is something else and not the thermostat.
However, as mentioned earlier, running the engine without the thermostat may make you believe your issue is the thermostat even when it is not. On the other hand, you automatically lose all the other advantages of running the engine with a thermostat as earlier discussed above.
However, a faulty thermostat can cause prolonged overheating on an automobile which could cause other engine components to get faulty. For example, due to severe engine temperatures, the cylinder head gaskets may blow off causing the cylinder heads to warp.
So if the thermostat test proves a faulty thermostat but when replaced with a new one still the engine overheats, it means your technician has to look further into other engine components but not demonise the thermostat.
Blocked radiators cores, leaking hose pipes, faulty Thermo switch, faulty cooling fans, low coolant level, failed water pump, are just a few of the many causes of overheating; when any of the above is faulty, fingers may quickly point to a thermostat.
Because when the thermostat is removed, the reaction is slowed down because of the coolant’s free flow, both the technician and car owner seem to be convinced that indeed the cause was the thermostat.
Digging deeper and wanting to find the real cause should be a primary role of every technician without jumping into conclusions. The bottom line is, your engine is not meant to run without a thermostat. Remove it and be ready to face the consequences.