Operation and maintenance manual

Cooling System QSB4.5 and QSB6.7
Page 7-2 Section 7 - Maintenance Procedures at 2000 Hours or 2 Years
Measure the total carbon deposit thickness inside the air
discharge line as shown. If the total carbon deposit (X +
X) exceeds 2 mm [1/16 in], clean and inspect the cylinder
head, the valve assembly, and the discharge line.
Replace if necessary. Contact the Cummins Authorized
Repair Location for procedures.
If the total carbon deposit exceeds specifications,
continue checking the air discharge line connections up to
the first tank until total carbon deposit is less than 2 mm
[1/16 in]. Clean or replace any lines or connections that
exceed this specification.
Inspect any air driers, splitter valves, pressure relief
valves, and alcohol injectors for carbon deposits or
malfunctioning parts. Inspect for air leaks. Maintain and
repair the parts according to the manufacturer's
specifications.
Cooling System
General Information
WARNING
Do not remove the pressure cap from a hot engine.
Wait until the coolant temperature is below 50°C
[120°F] before removing the pressure cap. Heated
coolant spray or steam can cause personal injury.
NOTE: Never use a sealing additive to stop leaks in the
coolant system. This can result in coolant system plugging
and inadequate coolant flow, causing the engine to
overheat.
The engine coolant level must be checked daily.