LO 11-6 Identify and describe the construction features, types, and applications of the diesel engine cooling components

Water Filters
Water filters on diesel engines, if equipped, perform two primary purposes. First, they remove sediment, rust, and dissolved particles, which cause abrasive damage to the cooling system. Removal contributes to longer water pump life and minimizes cooling system deposits. Second, they supply DCAs to the coolant. Filters contain pucks of DCA additive, which is dissolved within minutes of coolant circulating through the filter. The quantity of additive required for the maintenance of the cooling system is adjusted by selecting the appropriate filter. For example, some filters are prepared with no DCA while others may have 2, 4, or 18 units of DCA. When servicing the vehicle, the technician must select the appropriate filter for the cooling system capacity and the DCA requirement. This information is located in the vehicle service manual.

Diesel engines without water filters usually use SCA in LLC that does not require additives when it is fully formulated. SCA is a liquid used to condition the cooling system if required. With the increased use of ELC, which may only require the use of an extender halfway through the coolant’s service life, if at all, coolant filters are generally not installed in order to prevent the contamination of the coolant with powdered DCA.