Seizure due to overheating centred around the piston skirt
DESCRIPTION OF THE DAMAGE
- The piston skirt has seized on both sides.
- The surface of the seizure marks has a dark discolouration and is rough and severely broken up.
- The piston ring zone is often only slightly damaged or not damaged at all.
DAMAGE ASSESSMENT
Severe overheating of the engine has caused the lubrication on the cylinder sliding surface to completely break down. This has caused a seizure due to lack of lubrication with a heavily broken up piston skirt. The damage is centred on the skirt area; there are no seizure marks around the piston head. It is thus possible to exclude engine-based overstressing caused by abnormal combustion.
POSSIBLE CAUSES FOR THE DAMAGE
- Overheating engine caused by the following malfunctions in the cooling system:
- lack of coolant
- dirt
- defective water pump
- faulty thermostat
- torn or slipping V-belt
- inadequately ventilated cooling systems.
- On air-cooled engines: overheating due to dirt deposits on the exterior of the cylinders, broken cooling ribs or failed or compromised cooling air ventilation.
Side info