An well-seasoned auto mechanic friend of mine, who I have the utmost respect for, and who has worked on the very models of trucks which we are working on when they were new, told me that the bypass oil filters did little, if anything at all to stop sludge from forming in the oil pan. He based this on observing the sludge in the oil pans of engines when he adjusted the babbit bearing oil clearance (a regularly scheduled procedure back in those days). Whether or not these engines had the bypass filters made no difference. There was always the same amount of sludge in the pan. These engines were in cars and trucks which he provided scheduled oil changes.
A bigger issue in those days was the high frequency of rotten rubber oil filter lines failing, causing loss of all of the oil, resulting in catastrophic engine failure if one was not a habitual gauge watcher.
Last edited by 52Carl; 01/20/2017 1:49 AM.
