REPLACING THE THERMOSTATIC ELEMENT As per last post, the Thermostatic control valve of this Yanmar diesel engine was faulty and not operating optimally hence the sudden rise in lube oil temperature. Lube oil cooler is in good condition and lube oil is within it's healthy running hours... But TCV was found faulty. The old Thermostatic control valve element was changed with a new spare 🛠️⚓🚢😀 | Master Engineer Fix