Neglecting maintenance intervals can result in performance issues and internal engine damage due to sludge deposits restricting the flow of lubricant to vital engine components. Evidence of lack of maintenance will normally show up in the oil filter and related housing. The filter media will be impacted with sludge deposits. Where applicable, the filter cap will contain the same deposits or sludge. When these conditions are present it is almost certain the same contamination is present in the oil pan, valve covers, cylinder heads and related components, camshaft/camshafts, oil supply and re- turn ports. While lack of maintenance can result in lubrication issues and worn or broken parts, minute deposits can result in under or over oil pressurization conditions.
Fixed displacement oil pumps contain an internal pressure regulating valve, while some applications may have the valve positioned in the engine block. The purpose of this valve is to maintain the oil pressure within a given PSI range determined by the vehicle manufacturer for a specific engine application. The valve is comprised of a plunger/ball and a calibrated spring tension. Once the oil pressure reaches a determined pressure, the plunger will move from its seat against the spring tension, diverting some of the oil back into the oil pan or the suction side of the oil pump, thereby maintaining the desired oil pressure in relation to changes in engine RPM. Major pressurization problems occur when the plunger sticks in the bore in which it travels. Stuck in the closed position, an over-pressurization condition will occur, and the evidence usually appears in the form of a distorted filter canister or blown oil filter gasket. Stuck in the open position, a loss of oil pressure will occur that can result in engine damage. The presence of any minute substance has the potential to stick the pressure regulating valve, resulting in a high or no oil pressure condition. Variable Displacement/Two Stage Pumps utilize a solenoid in the oil pump controlled by the powertrain control module. The effect of sludge deposits resulting from poor maintenance intervals can lead to a catastrophic event in the engine. When per- forming a service and sludge deposits are present, research the maintenance interval for the vehicle. Most likely you will determine the condition is due to a poor maintenance schedule. Document your observations on the repair order, as it may save your shop from liability. Following the vehicle manufacturer’s recommended maintenance interval can prevent the accumulation of these deposits.
There is more to an oil filter than the canister size and thread size. The physical size of the filter is not an indication of the efficiency of the filter. Filters of the same dimension may be constructed with a different filtration media or number of pleats, which affects the efficiency. A smaller size canister can have a higher efficiency rating than a larger one. The selection of an oil filter for a given application varies in relation to the media, porosity, surface area, total capacity and required by-pass valve setting. Filtration efficiency is a measure of the percentage of particles of a determined size that the filter can capture. The capacity is the amount of debris the oil filter can hold before a differential pressure results in the by-pass valve opening, allowing unfiltered oil to flow throughout the engine. With today’s technology, oil filter flow rates result in a higher-pressure differential across the filter media, which requires a higher by- pass valve setting. Filters that do not meet these specs will result in unfiltered oil flowing through the engine, promoting accelerated engine wear or oil pressure related symptoms.
While the oil pump is the heart of the engine, the lubricant is the life’s blood for the engine. Oil viscosity does make a difference. Modern engines incorporate precise bearing clearances, and they are comprised of special metals. They are equipped with new camshaft technology with variable valve timing, all of which requires special lubricants and filtration efficiency.
Summary: Follow the vehicle manufacturer’s recommend- ed service schedule, oil viscosity and filtration requirements for the application, or the vehicle owner may encounter some major expensive repairs.