An internal or external loss of coolant on your Cummins ISX 15 must be checked correctly in order to determine the root cause. Before troubleshooting, it is important to also determine the exact complaint by interviewing the driver and looking at the ECM information. Coolant loss is a major issue and must be repaired at the units next stop. The EGR cooler is one of the components that will leak and in some cases be diagnosed incorrectly. When troubleshooting loss of coolant, it is very important to use a knowledgeable shop to save you not only money, but also time.
Signs of coolant loss may vary from cylinder block to head, water pump, EGR cooler, Turbo actuator, coolant system lines or radiator. Coolant loss drown stream from exhaust can sometimes be mis identified as oil but, this could be a coolant and soot mixture. Testing soot deposits with test strips will identify whether there is coolant present. Pressure testing coolant system to aid in locating coolant leak is helpful but, when the leak is internal more components may need to be removed to help locate leak. In this case signs of coolant and soot mixture were showing at the button of v-band clamp behind turbo. After testing liquids at band clamp for coolant, it was confirmed that coolant was present in the exhaust system.
Further troubleshooting lead to the removal of the exhaust piping behind turbo to visually inspect the turbo housing outlet/exhaust side. Coolant deposits were found in the turbocharger turbine housing and can be identified as dried white deposits coating the inside of turbine housing. At this point the EGR cooler is suspected as the source of coolant loss and must be verified by removing the EGR cooler connection pipe to visually inspect the inlet of EGR cooler for signs of coolant.
After removing connection pipe, a visual inspection can verify if coolant is present. Removal of EGR cooler for pressure testing is required. Once EGR cooler is removed it can be properly pressure tested with test kit. If the measured pressure loss in the EGR cooler is more than 15 psi in 15 minutes the EGR cooler is not usable.