ENGINE AR-PRIMARY 3999112 - Caterpillar

Leakage Around Oil Filter Seal
Naturally-aspirated 3208 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 the passages on both the inside and the outside of the guide; burrs can prevent free operation of the relief valve.
Do not use the 1W3852 Shield with a 1W1789 Relief Valve Guide that has not had modifications.
Illustration 1. Location of the relief valve guide.
Illustration 2. Location of the three holes that need to be made larger.