1985/04/01 Caterpillar

3408 And 3412 Industrial, Marine And Generator Set Engines

It can be necessary to install as many as three water temperature protection devices on the above engines. In some field installations, the high water temperature shutoff contactor, the high water temperature prealarm contactor and the electric sender for the water temperature gauge have been installed in undesirable locations on the engines. The correct functioning of these protection devices can depend on where they are installed on a particular engine arrangement. If these protection devices are installed too close to the exhaust or the turbocharger, the units can fail. If they are installed in poor flow areas, the units may not give accurate readings.

If there are problems with reliability or installation of these water temperature protection devices, use the following illustrations and instructions for best results in each arrangement.

Preferred Locations To Install Devices On Engines With Radiators

Illustration 1. Installation locations for engines with radiators.

1. On turbocharged (T) and turbocharged and aftercooled (TA) engines with radiators, install the temperature shutoff contactor in Location (A).

2. On T and TA engines with radiators, use the 7W2967 Adapter (see Illustrations 2 and 3) and install the temperature prealarm contactor group in Location (D).

3. Use Locations (B), (C), and (E) in the cylinder heads, for other, smaller temperature protection devices.

NOTE: On engines equipped with aftercoolers, the aftercooler water inlet tube must be removed and reinstalled so that these water temperature protection devices can be installed in Locations (B), (C) and (E).

Illustration 2. 7W2967 Adapter Group.

Illustration 3. Prealarm contactor installation for engines with radiators.

Preferred Locations To Install Devices On Engines With Expansion Tanks

Illustration 4. Installation locations for engines with expansion tanks.

1. On T and TA engines with expansion tanks, install the temperature shutoff contactor in Location (A).

2. On T and TA engines with expansion tanks, install the temperature prealarm contactor group in Location (B).

3. Use Locations (C), (D) and (E) in the cylinder heads, for other, smaller water temperature protection devices.

NOTE: On engines equipped with aftercoolers, the aftercooler water inlet tube must be removed and reinstalled so that these water temperature protection devices can be installed in Locations (C), (D) and (E). Location F is not used on these engines (expansion tank).