LINE-FUEL INJECTION 2903911 - Caterpillar

3406B Truck Engines (7FB)Investigation indicates that some 4N1156 and 4W4014 Gaskets are being replaced unnecessarily to stop coolant leakage. The 4N1156 Gasket goes between the coolant manifold and the cylinder head. The 4W4014 Gasket goes between the temperature regulator housing and the coolant manifold. See the illustration. Before replacing these gaskets, check the tightening torque on the bolts that fasten the regulator housing to the coolant manifold and the bolts that fasten the coolant manifold to the cylinder head. Bolt (A) in the illustration is not accessible and does not need to be checked. If the bolts begin to turn at less than 23 N m (17 lb ft), continue tightening to a torque of 43 7 N m (32 5 lb ft). If the bolts do not begin to turn at a torque of less than 23 N m (17 lb ft), they are properly tightened. If the bolts are properly tightened, and there is still coolant leakage, replace the gaskets. When replacing the 4N1156 and 4W4014 Gaskets, tighten the bolts to a torque of 43 7 N m (32 5 lb ft).
Location of components.