THE introduction of the oil filter into the lubricating system of internal-combustion engines marked a distinct advancement, Mr. Wolf states. However, he adds, due to the varying combination of working conditions, the operator who dreams that all lubrication problems are eliminated by the use of oil filters is due for a rude awakening. He continues to remark that any valuable tool can be abused if full cognizance is not taken of its possible shortcomings, and he enumerates those of the filter to form a basis of a true appraisal of its intrinsic worth.
Mr. Wolf notes that conflicting opinions are heard regarding filters due to the widely different circumstances under which identical equipment is operated. In stop-and-start operations, light delivery trucks and some passenger cars never have the engine warm enough in extremely cold weather to permit functioning of the filter, he points out. He also states that, at the other extreme, oil oxidation through high engine temperatures can produce materials that will clog it. Improper installations, type of filtering media, filter capacities, frequency of cleaning or replacing elements, neglect of servicing, moisture accumulation, oil acidity determinations, miscibility of undesirables in the lubricating oil, mechanical versus chemical filters, and the removal of additives, are some of the topics discussed by the author, with conclusions based upon field and laboratory studies.