What Does an Oil Filter Do?

The oil filter gets contaminants out of engine oil so the oil can keep the engine clean, according to Mobil. Contaminants in unfiltered oil can develop into hard particles that damage surfaces inside the engine, such as machined components and bearing surfaces.

The Purpose of Oil in an Engine

A vehicle's engine exists to convert fuel into the energy that's required to move a car, according to Firestone Complete Auto Care. The process that's involved in converting the fuel to energy takes a lot of moving parts, and motor oil is necessary to keep the moving parts lubricated. Properly lubricated moving parts inside of an engine make the engine more efficient and productive, meaning it produces more energy to move the car while using less fuel than it would if it were worn out. That's where the oil filter comes in. It's a key component in keeping the lubrication process working effectively.

Oil Filter Outer Construction

The part of an oil filter you can see is the outer metal can. It has a gasket that seals against the car's engine on one end and is a sealed metal on the other end. The sealing gasket is seated on the can's base plate, according to Mobil. Just inside the sealing gasket, there's a series of perforated holes as well as threaded center hole that aligns with the engine block's oil filter assembly.

Oil Filter Inner Construction

While you can't see an oil filter's inner construction, that's where the important part of the work is done by the filter. The inner filter material is typically crafted from synthetic fiber, according to Mobil. Engine oil is pumped into the filter, and once it's in there, the dirty oil is pushed into the holes on the base plate that are found just inside the sealing gasket. The pressure forces the dirty oil through the synthetic filter material, back out the central hole and it finally goes back into the engine.

Two Types of Oil Filters

There are two main types of oil filters, according to Firestone Complete Auto Care. One is a compact canister that is removed and installed as s lone component. The second type of oil filter uses a separate filter attached to a cap inside the filter housing, and it takes more work to change than the canister style filter. Your owner's manual is the best source of information on which the two is best for your car.

Shopping for Oil Filters

When you're shopping for oil filters, you can use an oil filter reference chart or oil filter catalog to find the oil filter numbers for your vehicle. It's extremely important to get the oil filter that's specifically designed for your vehicle, according to Mobil. While many filters look similar from the outside, the sealing gasket and threading since the center hole varies, and if both the gasket and threading don't align perfectly with the assembly unit on your engine block, it could fall off and your oil could run out, or if the filter is loose, all your oil could leak out of the engine block. Serious engine damage can result if these things happen.