Can You Afford a Cheap Oil Filter?

We recently performed an oil change on a BMW N55 engine, and what we found caused raised eyebrows all around the shop. The problem was the condition of the oil filter. It wasn’t the Original Equipment Manufacturer (OEM) filter, and that’s a bad thing. Here’s why.

The Importance of Filtration

Oil is the blood of your engine, and like blood, one of its functions is to carry away contaminants that would otherwise cause problems. Every time you start a cold engine, there’s a second or two of metal-to-metal contact at various places before the oil begins providing lubrication. Piston rings slide in the cylinder liners, valves move in their guides, and the crankshaft and camshafts rotate. That contact causes microscopic amounts of wear, with tiny slivers of metal being carried away by the oil.

These slivers would cause more wear and damage if it weren’t for the oil filter. That works by passing the oil through a filter element. Over time the element fills up, and eventually, you need to bring your car into EurAuto Shop in Plano, TX, for an oil change and filter replacement.

The BMW N55 Oil Filter

For many years oil filters were of a “spin-on” canister design. This hid the filter element inside a metal housing. You, or the oil change technician, went under the car, unscrewed the old filter, and screwed on a new one.

Modern engines do things differently. BMW’s N55 engine, for example, has a cartridge-style filter. This is held in a housing that the technician opens up when it’s time for a filter change. Two advantages of this newer design are that there’s less waste (no metal canister,) and you can see the condition of the filter element.

The Problem With Cheap Filters

We started this blog post by describing how we removed a non-OEM filter from the housing on an N55 engine. We knew it wasn’t the OEM piece because it looked pretty different. We could also see deformation in the folds of the filter element.

Two critical things about oil filters are that they must seal in the housing, so oil can’t bypass the filter element and its quality.

OEM filters are manufactured to tolerances specified by the engine builder. Tighter tolerances are harder to achieve, and that’s one of the things that makes them more expensive. However, it also ensures an excellent fit in the housing. A cheaper filter might fit, but it may be just a little loose, and oil under pressure doesn’t need much room to find a way past.

The filter element determines how well the filter traps contaminants and how much filtration capacity it has. Basically, the element fills up. A high-quality element has a large thick surface area, and it has tiny pores for the oil to pass through. Put together; these three factors ensure it does an excellent job of cleaning the oil for a long time and without imposing a significant pressure drop.

To put it simply, a high-quality filter does a better job of protecting your engine from contamination in the oil. It should also be clear why a good filter costs a little more.

Don’t Go Cheap, Go With EurAuto Shop

With any car, but especially a high-end one, you want to look after it. Regular oil changes are part of that, and we’d also stress the importance of using a quality oil filter. If you need an oil change in Plano, TX, come to us. We’ll take good care of your car.