The following procedure covers common troubleshooting steps to help identify:
โข Engine overheat causes. See the Initial Check section of this procedure.
NOTE: At the end of this procedure, a worksheet is provided to record any measured values taken during
troubleshooting. The worksheet will help in gathering and analyzing the data.
โข External and internal coolant leaks/loss. See the Pressure Test section of this procedure.
โข Combustion gas leaks into the cooling system. See the Test section of this procedure.
If the coolant reaches an unacceptable level in the recovery/expansion tank, a fault code should become active that will illuminate an instrument lamp and impose a power derate. This low level is detected by a coolant level switch mounted in the coolant surge/recovery tank.
In the event of a cooling system-related malfunction, it is recommended that coolant level switches be checked for
proper operation. Refer to the OEM service manual for operational checks and repairs.
Removal and installation of the coolant level switch for diagnostics is NOT recommended. This poses a high likelihood of damage, due to the plastic construction of the switch. The coolant level switch must only be removed
from the surge/recovery tank when replacing it with a new switch. Be certain not to overtighten the switch when
installing. Most switches have a very low torque value, which can be found in the OEM service manual.
Coolant level switches are very susceptible to improper Ph levels. For this and other reasons, it is imperative that the
coolant be maintained in accordance with Cumminsยฎ Coolant Requirements and Maintenance, Bulletin 3666132.
