Slow Acceleration Caterpillar

Slow Acceleration

Usage:

ENGINES3176C (6BW),
3196 (2XR) MARINE ENGINES

Problem:

Some 3176C and 3196 Engines may develop aftercooler core or seawater connector leaks. These leaks may allow seawater to enter the engine through the intake manifold. If this is not corrected, severe internal damage may occur and cause slow acceleration in the 1200-1500 rpm range, which may be accompanied by exhaust smoke.

Solution:

A: For engines not yet experiencing slow acceleration problems:

If an oil analysis shows that there is salt in the oil (special test for salt), remove the aftercooler core and pressurize the core to 30 psi air pressure. Submerge the core in water and check for air leaks. If the core leaks it should be replaced with a new 161-9898 Aftercooler Core.

NOTE: Drill out the 9.50 mm (0.374 inch) holes in the 189-5801 Adapter to 10.50 mm (0.402 inch) before installation.

NOTE: If the aluminum adapters are corroded, or do not align properly at disassembly, check the location for the 77.0 mm (3.03 inch) diameter bore in the 104-8009 Aftercooler Housing. Check the distance from the nearest edge of the 77.0 mm (3.03 inch) diameter bore to the aftercooler core mounting face. If this distance is more than 1.50 mm (0.060 inch) from the nominal 16.50 mm (0.650 inch), replace the aftercooler housing.

Replace the aluminum aftercooler adapters with the new MODIFIED 189-5801 Brass Adapters and install the new design 171-4358 O-rings in the sea water connections to the aftercooler core. The aluminum adapters can leak and corrode, allowing seawater to leak into the engine.

NOTE: If the engine is currently performing satisfactorily, that is, no slow acceleration has been observed, do not remove the cylinder head as there is no indication of internal engine damage.

B: For engines experiencing slow acceleration in the 1200-1500 rpm range:

NOTE: Drill out the 9.50 mm (0.374 inch) holes in the 189-5801 Adapter to 10.50 mm (0.402 inch) before installation.

If the oil analysis indicates that salt is in the oil (special test for salt), and slow acceleration is a problem, remove the cylinder head. If salt water has been entering the engine from the aftercooler, one or more of the three ports in the exhaust manifold should show severe rust. Particular attention should be paid to the cylinders where water entry is indicated (usually cylinders 5 & 6 on rear down installations). Carefully inspect valve seating faces and valve seat inserts (with good light and magnification) on those cylinders. The valve seating face should be smooth. The valve seat insert should be shiny where the valve is seating, and not corroded away on the inside diameter. If a problem is evident, replace the cylinder head with a 0R-7963 Remanufactured Cylinder Head.

Also, inspect the cylinder liners for wear in the area of the top 1 to 2 inches of ring travel. If the liner cross hatch is worn excessively or evidence of damaged rings is present, replace that cylinder pack with 0R-8189 Remanufactured Cylinder Pack on 3196 engines (0R-8187 Remanufactured Cylinder Pack on 3176C engines). It is not necessary to replace all the cylinder packs.

Also inspect the fuel injector for tip damage in cylinders damaged by the seawater, and replace as necessary.

If no salt is found in the oil, and no aftercooler core or adapter leakage is found, and yet there is slow acceleration without known cause, call the factory at 309-578-9015 for assistance.

NOTE: The root cause of this problem, and design changes (if any) required to the aftercooler core, is currently under investigation.

NOTE: If this problem occurs on a 3176B engine, contact your Product Support Representative for guidance.