ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 008-083   Keel Cooler

The temperature and pressure differential tests can be conducted at the same time, if the pressure connection allows the temperature probe to enter the coolant flow completely.

NOTE: This test
must be done using a blocked open thermostat.

Install temperature probes into the inlet and outlet test ports of the keel cooler thermostat housing.

Operate the engine under rated rpm and load until the engine temperature reaches its maximum. Record the inlet and outlet coolant temperature.

A temperature differential of 25°C [45°F] or greater is required for adequate system cooling. If the temperature differential meets this specification, test the coolant pressure differential.

If the temperature difference is less than 25°C [45°F], inspect the vessel’s keel coolers. Some problems with keel coolers that can cause a high coolant temperature differential include:

1. keel cooler size is too small
2. seawater temperature is too hot
3. marine growth on the keel cooler
4. fouling to the inside of the keel cooler
5. internal damage to the keel cooler
6. external damage to the keel cooler.

Refer to the keel cooler OEM for troubleshooting and repair manual.

Install test fittings and gauges into the inlet and outlet of the keel cooler thermostat housing.

Operate the engine under rated rpm and load until the engine temperature reaches it’s maximum. Record the inlet and outlet coolant pressure. If the pressure difference is less than 34 kPa [5 psi], remove and test the keel cooler thermostat. Refer to Procedure
008-014.

If the pressure difference is greater than 34 kPa [5 psi], inspect the vessel’s keel coolers. Some problems with keel coolers that can cause high differential pressure are:

1. blockage in the keel cooling system
2. internal damage to the keel cooler.

Refer to the OEM for troubleshooting and repair manual.