The thermostats are the signal agent of the engine’s cooling unit, this is so because they constantly monitor the temperature of the coolant and correctly regulate the coolant flow through the radiator to obtain and keep the optimum engine operating temperature.
Like other part, thermostat don’t last forever. There are two situation for failing thermostats:
- If the thermostat gets stuck in the open position, there is bound to be constant flow of coolant into the radiator making the engine to go cold. Overcooled engines operates inefficiently, which leads to increased fuel intake and higher emission rates and engine parts wearing out easily. In addition, the car interior will not be heated up properly.
- If the thermostat gets stuck in the closed position, the circulation of the engine coolant is blocked thus preventing the coolant from getting to the radiator to be cooled whichcauses the engine overheating.
The consequences of an “open thermostat failure” may be less dangerous than those of a “closed thermostat failure” but all seem undesirable. More so not every case of thermostat ageing and failure is clearly manifested in the form of an obvious failure pattern. Thus, preventive servicing is recommended.
HOW TO CHECK AND DIAGNOSE A FAILED THERMOSTAT
- LEAKING FROM THE MOUNTING SURFACE
Signs: Seepage, droplets or large coolant bleed marks on or all around the mounting unit or on the environment.
Causes: Improper irregular thermostat installation or incorrect use of seals/gaskets or/and sealant.
Recommendations: In cases of a newly installed thermostat: gently remove, inspect and reinstall the thermostat and correctly follow the torque directions and specification. Ensure seals/gaskets are in perfect order and are installed correctly. When sealant is prescribed, clean the rims of the part and the mounting housing and apply new sealant evenly through the edge of the parts. If the leakage is not because of an incorrectly installed new thermostat, the may be need to replace the thermostat
- RUST AND CORROSION
Signs: Rust, corrosion on the surfaces and housing of the thermostat.
Causes: Contaminated and spoilt coolant, non-compatible and or mixing coolants of different types and chemistries. Another cause may be a spoilt radiator pressure cap causing air bubbles, speeding up the rust process.
Recommendation: change the thermostat. And be sure too thoroughly and completely flush the cooling system and unit before installing the new thermostat and replace the system with the correct cars manufacturer’s recommended coolant type. Check the pressure cap and replace where need be.
- VISIBLE DEBRI BUILD-UP
Signs: Debris collets, sludge and scales build up on the inside, thus clogging the thermostat and stopping proper functioning of its individual components.
Causes: Contaminated and spoilt coolant, non-compatible coolant or mixing coolants of different types and chemistries.
Recommendations: Replace the thermostat. Before installing the new thermostat and refill the system with the correct vehicle manufacturer’s recommended coolant.