3406E and C15 Marine Engines Caterpillar

Illustration 1	g00107725
(1) Drain lines (2) Adapter (3) Valve (4) Plunger (5) Valve seat

The engine boost pressure forces plunger (4) to move down to valve seat (5). The plunger must close against the seat at a pressure of 27.5 kPa (4 psi). When the engine is stopped, the absence of boost pressure allows the plunger to rise to the open position, which allows condensation from the aftercooler to drain out.

The plunger must be able to move freely in order to close the system when the engine is running. The plunger must be able to move freely in order to allow condensation to drain from the aftercooler when the engine is stopped. Residue from normal engine operation could cause the plunger to stick.

1. Remove valve (3) from adapter (2). Check the valve in order to determine if plunger (4) moves freely. If the plunger does not move easily, clean the valve with solvent.

2. Remove drain lines (1). Check the lines for plugging. Clean the lines, if necessary. Pressure air or a flexible rod with a small diameter can be used to clean the lines.

3. Reassemble the aftercooler condensate drain valve. Refer to the Operation and Maintenance Manual for more information on the proper torques.