Checking the Cooling System

Checking the Cooling System - Gen 5 DD15 - Ops - #7628

Check the cooling system as follows:

  1. Make sure all draincocks in the cooling system are installed and are closed tightly.
  2. Fill the coolant overflow surge tank with approved coolant, until the coolant level stays between the low and full coolant marks on the tank. Do not overfill the coolant, as overfilling will cause the surge tank to push coolant out. See How to Select Coolants for more information.
  3. Entrapped air must be purged after filling the cooling system. To do this, warm up the engine with the pressure cap removed. With the transmission in neutral, increase engine speed to 1000 rpm and add coolant to the surge tank as needed.
  4. Check to make sure the front of the radiator and charge air cooler are unblocked and free of debris.
Note:
EA5,EB6
Parent topic: First Time Engine Operation
Document Number: 0000009699
Manual Publication Date: 2025-08-26
Topic Publication Date: 2026-02-05