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[Dave_Nowlin]

Duncan, I agree with you totally. One thing about most of these aftermarket filters is they achieve much of their efficiency through the use of tackifier. Tackifier does 2 things always. It migrates (blows off the filter downstream) and it dries out over time. As it dries it begins to release oily dirt which will build up on your turbo blades until it sluffs off as agglomerations of dirt directly into your engine. Filters that work because the pores are small enough to exclude dirt particles (strainers) are much safer in this application. In fact I wonder how many trucks which have had various types of problems with turbos or injectors have been equipped with these aftermarket filters. The really confusing thing here is that these filters have often been tested by Independent Laboratories to back up manufacturer claims. These tests are done by loading these filters with a test dust over a very short period of time. In these tests the filter cake isn't subjected to the constant vibration which the filter in your truck experiences. This vibration will cause some unloading of the filter. It isn't subjected to the heat either which causes accelerated drying of the tackifier. The loading isn't gradual over an extended period of time either which will effect how the dust loads into the filter. For this reason none of these tests run with medias which aren't true strainers are valid. They all will yield results which differ greatly from the real world environment your truck lives in.
Dave Nowlin