Why You Shouldn't Buy Cheap Oil Filters

Before we get into the nitty-gritty of types and differences between oil filters, it's necessary to understand what is an oil filter and how it works. An oil filter is a mechanical device that removes dirt, metal fragments, and contaminants to ensure a clean engine oil is circulated into the engine. It prevents the engine from wearing and ensures your engine keeps running healthily and smoothly. An oil filter features a metal can with a sealing gasket that is held against the engine's mating surface. The base plate or the tapping plate comprises perforated holes through which the unfiltered engine oil enters the oil filter after it is pushed by the engine oil pump. The oil is then pushed under pressure through the pleated filter media, where the contaminants get trapped. After the oil is filtered, it then moves out through the central hole where it re-enters into the engine. A few major components of an oil filter are as follows:

1. Tapping Plate: A tapping plate is an entry and exit point on the oil filter. It faces the engine and comprises small holes around the edge through which the oil flows into the filter. It also has a  hole at the center where the oil exits after it’s filtered and goes into the engine.

2. Filter Medium: A porous filter medium is located inside the oil filter and is usually made from cellulose and synthetic fibers which trap contaminants and dirt present in the engine oil. This filter media or filter medium is folded into pleats for a larger surface area.

3. Anti-Drain-Back Valve: It is a rubber or silicone valve that prevents oil from flowing back out of the oil filter when the engine is turned off. This allows the engine to receive oil immediately when the engine is started and prevents dry starts.

To many people, the oil filter is just a consumable product, and the price is the only factor taken into consideration while purchasing an oil filter. Though all oil filters look the same on the outside, the internal components and their quality can make a big difference. A basic understanding of the terms, parts, and various rating systems can allow you to make a wise decision while purchasing an oil filter for your vehicle. Some factors that will help you choose a good-quality oil filter and differentiate between a cheap one are as follows: 

1. Filter Element: Oil filter manufacturers use various types of filter media to trap dirt and contaminants in the engine oil. This oil filter media is usually pleated or folded, which provides the essential filter area and pore structure needed for unrestricted flow, dirt-holding capacity, and particle capture efficiency. The filter media is made of wood pulp (cellulose), cotton linters, synthetic materials, etc. However, new high-performance oil filters also use glass fibers or a composite of cellulose and glass. Cellulose filter media is made from paper and does not offer high dirt holding capacity compared to fiberglass or synthetic ones. Fiberglass or micro-glass filter media performs better than cellulose filter media because the fibers are manufactured to be 10 times finer than cellulose media. Synthetic filter media used in quality oil filters perform better than cellulose filters and are usually made of nylon, glass, or polyester. It contains more pores per square inch for a higher dirt-holding capacity. 

2. Micron Rating: A micron is equal to 1 millionth of a meter. A micron rating of an oil filter determines the capacity of an oil filter to remove contaminants by the size of the particle that it can retain. For example, a 25 micron-rated oil filter can filter contaminants sized 25 microns or higher. Similarly, a filter with a 40-micron rating can filter contaminants of 40 microns or larger. Therefore, a small micron-size oil filter traps finer contaminants in the engine oil and ensures lower wear rates and prolonged engine life.

3. Pressure-Flow Profile

Some cars are equipped with an oil pressure gauge which indicates the oil pressure and warns once it becomes too high. This can happen due to dirt accumulation in the oil filter media. In such a condition, the bypass valve gets actuated to ensure continuous oil flow. Usually, oil filters have a pressure differential rating of 10-12 Psi at which the bypass valve actuates. Oil filters with a low micron rating are designed for maximum filtration, which can also restrict the oil flow rate. Most oil filters are designed with the same pressure differential ratings of 10 to 12 psi. Some major suppliers of automobile oil filters provide pressure-flow ratings for their filters so you can make an informed decision.

4. Filter Efficiency: Stating a micron rating of a filter without filter efficiency can be misleading. A micron indicates the ability of an oil filter according to the size of the contaminants, whereas filter efficiency refers to the measure of the filter's ability to collect and retain particles. For example, if an oil filter is said to be 95% efficient at 40 microns, it means the filter can collect and retain 95% of the particles that are 40 microns in size. Both micron rating and filter efficiency should be considered while purchasing an oil filter for your vehicle. Typically, a cheap economy-grade oil filter will have a 95% capture efficiency at 40 microns with almost no protection from lower micron contaminants, which can seriously harm your engine.

5. Design And Construction: Oil filters are made from several materials like steel, plastic, etc. Cheap and economy oil filters use inferior-quality materials like plastic and have cardboard end discs that can not withstand long service intervals, repeated shocks, vibrations, and thermal cycles. In general, a good quality oil filter should have a strong burst-resistant steel canister, a flexible anti-drain-back valve that avoids backpressure and leakage at cold temperatures, a bypass relief valve that doesn't leak at normal pressures, and a filter element with high dirt holding capacity and filtration efficiency.

Generally speaking, spending a little more money on a good quality oil filter offers better filtration and performance. Lower-cost oil filters contain light-gauge material, loose filter materials, and poor-quality gaskets that don't allow the filter to last long. You should research the features and specifications of each oil filter to determine which suits your requirements. An inexpensive oil filter doesn't mean it's bad and a costly oil filter doesn't necessarily mean it's good. The price of an oil filter doesn't tell the quality of parts used in an oil filter. Therefore, it's important to consider the factors listed above before purchasing one. However, a cheap and generic oil filter won't last long and if things get worse, the filter media can break or fail, allowing chunks of debris to enter the oil passage and into the engine. Cheap oil filters can lead to several problems, like oil leaks due to ruptured seals, stripped threads, can burst, failed bypass valves, etc.