GASKET 2721956 - Caterpillar

All Naturally-Aspirated 3208 Truck EnginesDescription of Change: A new relief valve guide is used in the oil pump group for all naturally-aspirated 3208 Truck Engines. The new guide is identical to the former guide, except for the three oil passages farthest from the threads. These three oil passages on the new guide have a diameter of 6.00 mm (.236 "); these passages on the former guide have a diameter of 4.00 mm (.157 ").The larger passages decrease the maximum oil pressure caused when the engine is first started during cold weather.
Adaptable To: The new 2W4110 Relief Valve Guide is a direct replacement for the former 1W1789 Relief Valve Guide. The former guide still is available.The chart which follows has the "in effect" and "adaptable to" serial numbers for the 2W4110 Relief Valve Guide and for the 1W3852 Shield. Caterpillar's recommendation is that the 1W3852 Shield be installed with the 2W4110 Relief Valve Guide. The shield will not let too much oil flow toward the two front cylinders.
Leakage Around Oil Filter Seal
Naturally-aspirated 3208 Truck Engines, at times, have oil leakage past the oil filter seal at start-up during cold weather. Analysis of this problem has shown several possible causes.
... Damaged filter base. The contact surface for the oil filter seal is damaged so that an acceptable seal between the filter and base is not possible.... No lubrication on filter seal. If too little or no lubricant was put on the oil filter seal before it was installed, the seal was probably damaged during installation of the oil filter. Identification of this type of damage can be made by inspection of the seal. Look for stretch marks and/or a rippled (not smooth) seal surface.... Damaged or incorrectly (not correct) installed seals. Before an oil filter is installed, carefully inspect the seal to make sure that it is correctly installed and not damaged.... Oil filter not tightened correctly. To correctly install the filter after lubricant has been put on the seal, clean the filter base and tighten the filter by hand until the seal makes contact with the base. With a filter wrench, tighten the filter an added 3/4 turn.... Incorrect lubricant viscosity . Use of the wrong lubricant for the ambient (outside) temperature range can cause higher lubrication system pressures. See the correct Operation Guide for the correct oil type and grade.... Incorrect start-up procedure during cold weather. When an engine is first started in cold weather, it must be operated for at least five minutes at low idle with no load before its speed is increased and a load is added.The 2W4110 Relief Valve Guide and the 1W3852 Shield can be installed when the oil pan is removed for any type of service. If desired, the earlier 1W1789 Relief Valve Guide can be installed with the 1W3852 Shield if modifications are made to the guide.
To make the modification, use a 6.00 mm (.236") diameter bit to drill out the three holes farthest from the threads. Remove all burrs from