The design of the Cadillac Oil Filter is made so it is possible to remove the minute carbon particulates from the engine oil that the combustion of the fuel creates. Inside of the oil filter is a paper element that traps the carbon particulates so the oil that reaches the moving parts of your Cadillac engine can be lubricated with the cleanest possible oil that can be provided.
The interval that the oil and the oil filter are to be changed is set at either 3,000 miles or three months. These are the results of the calculations that were run in determining the amount of particulates that would be created by the engine which will begin to saturate the paper element of the oil filter. Once saturation has occurred, the flow of oil through the filter element will naturally decrease reducing the amount of clean oil that will be available for the moving components of your Cadillac engine.
Once the saturation limit is exceeded in the Cadillac oil filter, the bypass valve will close off the filter from the engine lubricating system. This has to occur because the amount of oil that can flow out of the filter is reduced to the point that the moving components in the engine would not be receiving the appropriate amount.
The main reason for an oil change on your Cadillac is not to really change the oil because it is worn out; it is because it has become too dirty to be fully effective in the engine. If the oil filer is not replaced with a new one, the engine will prematurely wear due to the contaminates in the oil that are reaching the moving parts scoring them.