1988/05/01 Caterpillar

To minimize corrosion and/or carbon build-up on internal engine components, the jacket water temperature must be kept above 79 °C (175°F). If the cab heating and/or cooling temperature are not high enough, use any one or all of the suggestions that follow to increase the coolant temperature and prevent engine overcooling on 3306B Truck Engines.

... Install a winter front on the radiator grill and adjust the air flow to prevent overcooling of the radiator. For ATAAC engines, a 4W2682 Indicator (air temperature gauge) can be used to monitor the air temperature of the intake manifold. The air temperature in the intake manifold should not exceed 70 °C (160°F) for ATAAC engines with the winter front installed.

... Install a new 7C3095 Water Temperature Regulator. The regulator has an opening temperature of 88 °C (190°F) and can be used as a direct replacement for the existing 4W4842 Water Temperature Regulator. The new regulator has a flange that is coated with rubber. This helps prevent leakage around the regulator that can cause overcooling.

... Install a 5P3422 Tee, 8N4485 Vent Line Valve Assembly, and 6V7183 Hose Connector in the vent line between the cylinder head and radiator. See the illustrations. The check valve will shut off the coolant circulation from the vent line when all of the air is vented from the head.

Add these parts to the aftercooler water lines group on JWAC (jacket water aftercooled) engines.

Add these parts to the housing and regulator group on ATAAC (air-to-air aftercooled) engines.