C3.4B Industrial Engine Caterpillar

Illustration 1	g03676503
Typical example

If contamination of the Diesel Exhaust Fluid (DEF) is suspected, the DEF tank (3) will need to be drained and the DEF tank flushed.

1. Ensure that the purging of the DEF system has been completed.

   Note: Ensure that the vessel that will be used is large enough to collect the fluid to be drained.

2. Position the vessel below the drain plug (4). Remove the filler cap (1) Remove the drain plug and allow the fluid to drain.

3. Remove the Manifold (DEF Heater) (2). Refer to Disassembly and Assembly, "Manifold (DEF Heater)-Remove and Install" after draining the fluid.

4. If necessary, remove the DEF filler screen. For more information, refer to this Operation and Maintenance Manual, "DEF Filler Screen - Clean".

The DEF tank must be flushed after draining. Flush the tank with deionized water Ensure that all the flushing agents have been drained. Install the Manifold (DEF Heater) (2).

1. If necessary, Install the DEF filler screen. For more information, refer to this Operation and Maintenance Manual, "DEF Filler Screen - Clean".

2. Install the drain plug (3). Tighten the drain plug to a torque of 6 N·m (53 lb in). Remove the vessel used for draining. Dispose of the drain fluid in accordance with local regulation.

   Note: At key on after the tank has been drained completely the DEF level gauge will show the last known DEF level. The DEF level gauge will start working accurately as the tank is being filled with DEF.

3. Refill the DEF tank (1). Refer to this Operation and Maintenance Manual, "Diesel Exhaust Fluid - Fill" for more information.

If the DEF tank has been fill with another fluid other than DEF, then contact your Cat dealer.