Oil Filter Magnets
In the course of regular driving, a great mount of dirt, dust and grime can get into the car’s hood. Unfiltered, this can get into you engine and reap havoc on both the engine and the oils within it. That’s where oil filters come in. When the first cars were made there were no oil filters, and so the oil had to be replaced every month or so to wash out all of the dirt that was running through the engine. Of course, since we drive so much now, it likely wouldn’t take us more than a week to completely ruin our oil supply if left unfiltered.
Oil filters, and your car’s oil supply in general, is extremely important to the engine, and without oil, you’re engine will likely be destroyed in a matter of minutes or hours of driving. But a dirty oil supply is also very bad for the engine. A dirty or clogged oil filter will allow more dirt into the engine, and worse, that general grime will begin to contaminate the oil supply, turning it to sludge. As you might have guessed, this puts even more strain on the engine, because it the oil becomes less effective at managing heat, lubricating the gears, and reducing the friction that inflicts wear and tear on the engine.
The purpose of oil filter magnets is to attract any spare metal contaminants that the filter might miss. They are usually placed at the bottom of the filter, where (ideally) they can remove the particles from the flow of oil and keep them there, away from the engine, until your next oil change. In theory, the magnet is picking up stray metallic contaminants that the oil filter, by itself, can’t catch. Magnet makers claim that this could extend engine life, improve gas mileage and possibly even warn you of a catastrophic engine problem.
The question is whether and how well oil filter magnets work, and the results here aren’t great. Most oil magnets are marketed as doing things that they don’t and can’t possibly do. Any reports or advertisements that say that oil magnets can get you better mileage, give your car more power, reduce emissions or let you change your oil less often are almost certainly false, or those benefits are so minor as to be nonexistent. The truth is that oil filter magnets simply don’t have that great of an impact on your car’s performance.
On the other hand, iron particles are some of the most common oil contaminants. It’s almost a given that if you install a magnet, it will pick up some of these particles. Over time, that can actually decrease the wear and tear on your engine by a somewhat significant amount. Also, if your engine is actually shredding off metal into the oil for some reason, you’ll be able to tell. This would mean that your engine is about to experience some sort of critical failure, and you’ll need to take your car to a mechanic immediately.
Are oil filter magnets worth it? Maybe. They only cost around $10, so it’s not as if you’re paying some huge expense. And if your oil is picking up iron that’s not from your engine, or if you detect a critical problem early, it could really be worth that money. Just don’t believe the advertisements that the makers of the magnets have, because the chances are that your magnet isn’t going to accomplish anything major. Likely, it will pick up a few insignificant particles over time, and that might do a minimal service to your engine. But that isn’t any reason to put off actually changing the filter or oil, which is easily the most important step you can take in regards to your oil supply.
Comment by t freeland on 27 January 2011:
Many oil filter magnets are indeed marketed with exaggeration of benefits. However, the best magnets (Neodymium Iron Boron) can remove many abrasive particles from lubricating oil, on not just particles which are normally considered magnetic. These particles can be smaller than 1/2 micron in size. Most oil filters are designed to handle particles down to the 30 to 40 micron range, some of the better ones down to 20 microns. Clearances between part in a typical automotive engine run from 2 to 22 microns. For this reason, most of the wear that an engine experiences, comes from particles smaller that the oil filter stops.
By removing particles which are larger that the clearance size, wear and friction are reduced. The reduction in friction is not so large, that any significant increase in mileage or engine output will be immediately noticed, but the effect over the long haul is meaningful.
Most of what oil filter magnet manufacturers claim, from what I have read, are real benefits. However, not all magnets are created equal. Material, design, and location of magnet matter to receive maximum benefit.