Filters and Magnets!

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Here is a very good, very cheap mod that actually works. Install magnets at your oil filter, oil pan drain bolt, and don’t forget your transmission, axles, and transfer case drain bolts! A little background info helps here. Oil filters have a minimum particle size that they can capture and a removal efficiency. This means a couple different things. There is a minimum size particle that can be trapped by your filters, measure in microns usually. A particle below this size, lets say 20 microns, will pass through the filter every time (nearly). The removal efficiency is the number of passes required for a particle above this minimum size to be trapped. A particle can not be trapped in a single pass in an automotive filter, because the filter would be too restrictive, and would either need to be much larger, or would restrict oil flow to a greater extent than acceptable.

The most damaging and significant contaminant in your automotive fluids are metal particles. These are the most destructive particles due to their high hardness, in general. The exception here is nickel, copper and aluminium, which are not that hard. These non-ferrous metals aren’t magnetic and won’t be affected by your new magnets anyway. We are going after steel and iron. Also, since these metal particles are created very gradually, by slight wear with each rpm, their particle size is extremely small. This is why magnetic separation helps in a way that a filter can’t.

There are a few different options for installing magnets, but the principle is very simple. Use the strongest magnet you can for as little money as possible.

A cheap option for spin on magnets is an internal washer style magnet. This type of magnet is actually used as OEM for Allison transmissions, and it works great. For those of us with cartridge type filters, such as BMW, Audi and others, this may be the only filter option, as the filter housings tend to be plastic.

Washer Type Magnets
Washer Type Magnets

You can also purchase magnetic wraps for your spin-on filters. These tend to be pricey, but if you feel like achieving a larger surface area, they are a good option. You can install a few coin magnets around the perimeter of your spin-on filter as well, for a little extra work.

Oil Filter Magnetic Wrap
Oil Filter Magnetic Wrap

Neodymium button magnets are a good option, especially drain plugs. For example:

10 Neodymium Magnets 1/2 x 1/8 inch Disc N48
10 Neodymium Magnets 1/2 x 1/8 inch Disc N48
These are approximately 1 dollar each, or 10 dollars for 10 magnets. Purchase whichever diameter makes the most sense for your application. Alternatively, you can purchase a drain bolt with a magnet permanently attached.

Magnetic Drain Bolt
Magnetic Drain Bolt
Magnetic Drain Bolt
Magnetic Drain Bolt

You’ll be amazed at what you find after 3-7 thousand miles. Magnets will also alert you to an internal engine problem, if you begin to see an increase in ferrous accumulation.

Have Fun and keep that engine protected!

-Leftlanebrain