If troubleshooting coolant in the fuel, fuel in the coolant, fuel in the oil, or oil in the fuel, pressurize the internal fuel
drain line in the cylinder head and check for leaks.
Remove the fuel drain line at the rear of the cylinder head.
Refer to Procedure 006-013 in Section 6.
If equipped with a quick disconnect fitting at the cylinder head, remove the check valve. Refer to Procedure 006-013 in Section 6.
Connect a regulated air supply hose to the cylinder head fuel drain port with a shutoff valve on the air supply side
of the pressure gauge.
Apply air pressure.
Shut off the air supply to the fuel drain port and monitor the pressure gauge reading. The pressure should hold
steady. If the pressure drops rapidly, check for leaks around the:
• Test fittings
• Fuel connectors at the cylinder head
• Remove the rocker lever cover and check for air bubbles around the injectors. Refer to Procedure 003-011 in Section 3.
• Remove the radiator cap and check for air bubbles in the cooling system.
If the source of the leak can not be determined, remove the cylinder head and pressure test the complete cylinder
head. See the Pressure Test section of this procedure.
Replace the cylinder head if necessary.
