20/11/2025
A persistent (and dangerous) misconception among some drivers and older mechanics is that removing the thermostat allows for continuous coolant flow, thus resulting in a better-cooled engine. However, as the image illustrates, this is a MYTH, and the actual reality is quite the opposite!
The Myth: Removing the Thermostat improves engine cooling.
Description: This belief is based on the premise that unrestricted flow prevents overheating.
Short-Term Effect: The gauge might drop slightly at first, but this does not equate to effective cooling efficiency.
The Reality: Removing the Thermostat damages the engine and compromises efficiency.
1. Permanently Low Operating Temperature:
The thermostat is designed to maintain the engine at its optimal operating temperature (usually around 90-105\text{°C}). Removing it causes the engine to run constantly too cold, leading to:
Increased Engine Wear: Due to poor lubrication of cold components and unnecessary thermal expansion later on.
Increased Emissions: A cold engine does not achieve optimal combustion efficiency.
2. Performance and Fuel Economy Issues:
The Engine Control Unit (ECU) relies on reaching the optimal temperature. If the engine remains cold, the computer continues to inject excessive fuel (assuming it's still warming up), leading to a significant increase in fuel consumption and reduced performance.
3. Eventual Overheating and "Hot Spots":
Without the thermostat, coolant flows too quickly through both the radiator and the engine block. This rapid flow does not allow enough time for the coolant to properly dissipate heat in the radiator, nor does it allow it sufficient time to absorb heat efficiently from the engine block. This can lead to localized overheating (Hot Spots) and sudden boiling.
Conclusion: The thermostat acts as a precise heat regulator. If your engine is overheating, the problem is either a faulty thermostat (stuck shut) or a failure in other cooling components (pump, radiator, fan), not the thermostat's presence itself.
