Car thermostat core
The damage to the car thermostat can lead to uncontrolled engine temperature, which is manifested as overheating of the engine or failure to reach the normal operating temperature. This, in turn, causes a series of performance and durability issues.
Core impact and specific manifestations
Thermostat damage can be divided into two states: stuck in the open position or stuck in the closed position. These two states have completely different effects on the vehicle.
Thermostat open (engine unable to heat up)
Fuel consumption significantly increases: The engine operates at a low temperature for a long time, and the fuel is not atomized properly. The computer will increase the fuel injection volume to maintain operation, and fuel consumption may increase by 10%-15%.
Heated air supply failure or extremely poor effect: The heat is continuously lost in the large circulation of the coolant, resulting in low air temperature from the heating system, which seriously affects the comfort of driving and riding in winter.
Increased engine wear and reduced power: At low temperatures, the engine oil has high viscosity, and the lubrication effect is reduced. The friction resistance of internal parts increases, accelerating wear and causing insufficient power output. At the same time, low combustion efficiency directly weakens power.
Thermostat closed (engine overheating)
High risk of engine damage: The coolant cannot enter the large circulation for heat dissipation, and the heat accumulates, which may cause the engine to "boil" (the coolant boils) and lead to damage of the cylinder gasket, piston pulling, and even engine failure.
Power loss and emission： Overheating may cause abnormal operation of components such as valves， reducing power output； at the same time， high temperature may cause the emission control equipment such as the three-way catalytic converter to fail， resulting in excessive exhaust emissions.
Related system chain damage： Continuous high temperature also damages the fuel system， lubrication system， etc.， significantly increasing the subsequent maintenance cost and complexity.
Identification methods for faults
In addition to observing abnormal readings on the water temperature gauge (long-term low temperature or rapid rise to the red line)， the following methods can be used to preliminarily determine：
Touch the temperature difference of the radiator water pipes： 3-5 minutes after cold engine startup， touch the upper and lower water pipes of the radiator. Under normal circumstances， the upper pipe is hotter first， and the lower pipe is hotter later. If the temperatures of both pipes are always the same or the temperature difference is extremely large (more than 15℃)， the thermostat may be faulty.
Pay attention to the changes in heated air and fuel consumption： If the heated air does not heat for a long time in winter， or if fuel consumption suddenly increases by 5%-10% recently， accompanied by unstable idle， these can be used as auxiliary clues for judgment.
Listen for abnormal sounds： There may be a "gurgling" sound or metal friction sound when the coolant circulates.
Recommendations for repair and maintenance
The impact of thermostat failure is progressive and interrelated， from performance decline to core component damage. Therefore：
Timely inspection and replacement： Once the above signs are detected， inspection should be carried out as soon as possible. The cost of replacing the thermostat itself is usually not high， but delaying the repair may lead to major engine repairs， with a huge cost.
Perform preventive inspections： It is recommended to conduct special inspections of the cooling system and thermostat when the vehicle has traveled 8-100，000 kilometers to prevent problems before they occur.
Do not remove it yourself： Removing the thermostat will cause the engine temperature to completely (lose control)， with slow warm-up at cold start and prone to overheating at high temperatures， which will comprehensively exacerbate fuel consumption， power loss and engine wear， and significantly shorten the engine's lifespan. When the temperature rises (water temperature above 85℃): The wax inside the thermostat core melts due to heat, causing a significant expansion in volume. This pushes the rubber tube and the push rod, overcoming the spring force, and gradually opens the valve leading to the radiator. The coolant then begins to flow through the radiator for a "large circulation", preventing the engine from overheating.
At normal operating temperatures (85–95℃): The thermostat core automatically adjusts the valve opening based on the real-time water temperature, achieving a dynamic balance between the large and small circulations, and maintaining stable engine temperature.
The thermostat core is usually of a "wax type" structure, with wax filled inside that contains copper powder. The copper powder can quickly conduct heat, improving the response speed of temperature sensing. Its working state directly determines the efficiency of the engine's thermal management. If there are "always-open" or "always-closed" faults, it can lead to slow preheating, insufficient warm air, increased fuel consumption, or engine overheating, etc., which are serious problems.
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