ANALISIS PENINGKATAN COOLANT TEMPERATURE PADA ENGINE DIESEL CAT C-15 AKIBAT KONTAMINASI OLI ENGINE DENGAN AIR RADIATOR SERTA EFISIENSI OVERHAUL

CAT C-15 diesel engines are widely used in heavy equipment due to their durability and efficiency. However, coolant temperature stability is very important to maintain engine performance. This study analyzes the increase in coolant temperature due to contamination between engine oil and radiator water caused by cracks in the cylinder liner. The methods used include a qualitative descriptive approach with Root Cause Analysis (RCA) and Fishbone Diagram techniques. Data were obtained from PSRPT and dyno tests before and after overhaul. The results showed that the coolant temperature before overhaul was in the range of 122.0 °F to 248.0 °F, while after repair it decreased to 163.0 °F to 192.0 °F. Cracks in the No. 2 cylinder liner became the entry point for radiator water into the lubrication system, causing fluid mixing, impaired heat transfer, and decreased engine performance. These findings emphasize the importance of monitoring oil and coolant conditions as part of a preventive maintenance strategy for diesel engines in severe work environments.