Recently my curiosity drove me to explore what BITOGer's were saying about using magnets in engine oil. Below is a summary of the comments that others have made. In most cases I've provided a link to one of the comments which was making a claim, however, somehow I did lose track of some of the links. The are broken down results into positive, negative, and technique comments.
Positive:
Several BITOGer's have suggested that magnets may catch particles which would be too small for the filter to catch. In one thread particles were examined under a microscope showing that what the magnet caught was below the filter's capacity (1). Another mentioned that particles all the way down to 2 microns cause additional wear thus if the magnet catches these it could be helping (2).
Additional, comments mention that some OEM oil plugs contain magnets and that transmissions often have magnets in them suggesting that some manufactures think magnets are a good idea (3). Often a threat will include at least one post which states that it seems like even if it can't be proven that magnets help it seems like it can't hurt so if it improves your comfort level use them (7).
Negative:
There were also plenty of negative comments. In many threads there was at least one skeptic who didn't think magnets would catch particles smaller than the filter element can catch, or that if there are particles are large enough for a magnet to catch it suggests that really serious unusual wear is occurring (5, 6). Additionally, many have suggested that the same wear still occurs and even if iron is lower in UOA it's only because the wear particles are on the magnet and not detectable in the UOA (unfortunately I lost the links for these posts...but there were plenty of them and they can be found using the search feature). In one comments a user referenced an article from Noria's Machinery Lubrication which suggested that the use of magnets may cause particles to be released in a particle cloud, apparently from a bust of flow or jolt...etc, and thus resulting in a clog upstream (4). In the same comment (and in other threads) the concern is raised that this could lead to magnetized particles which could then stick to critical parts of the engine. Probably the most negative comment though was one which stated that in a study conducted over 10 years ago by a fleet operation the use of magnets made virtually no difference in UOA vs a control group that was not using magnents (8).
Techniques:
A few have suggested that placing a magnet on the oil pan might be a good technique (9). However, in the same thread other commented that this is probably a bad plan as particles may remain stuck to the pan even though the magnet is removed before draining the oil. Thus, this technique could lead to years of particles collecting in the same place and possible resulting in a cloud of particles being released sometime in the future. So the recommendation is to place magnets on the oil filter. In almost every thread there is at least one post advocating the use of magnets from old hard drives (10). At least one comment mentions that they last a very long time (at least 8 years) in spite of the high heat conditions. Other comments mention magnets that can be placed inside the return side of the filter, though some BITOGer's are concerned about flow restriction with this (sorry lost the link). Another post mentioned epoxying a magnet to the oil plug and others have mentioned simply purchasing a magnetic drain plug (sorry no link again). Additionally, there are plenty of after market magnets which can be purchased which will attaches to the side or the bottom of the filter. This link provides a pic of what one side mounted magnet caught (11). Of course there are plenty more pics if you search the filter forum for magnet.
Quick Summary:
The pictures posted in the forums clearly show that magnets in oil do catch particles of iron which are in the oil. However, it seems like the only scientific information we have to go with here is the fleet study which indicated that magnets don't really make a difference the actual wear that is occurring. Additionally, the concerns about particle clouds seem like a bit of a deterrent to me. I still have some other concerns such as could additives be trapped by the magnet. I know the additives are not ferrous but I'm aware that there are some other non-ferrous minerals which are attracted to magnets, but I'm not sure which one's they are or if they are used as additives. I've also seen concerns posted about magnets interfering with bypass valves but generally the replies suggest that should not be a problem (12).
Any other thoughts on this topic? I appologise for the length of this post...there was a lot of data out there.
1. http://www.bobistheoilguy.com/forums/ubb...985#Post1611773
2. http://www.bobistheoilguy.com/forums/ubb...287#Post1326372
3. http://www.bobistheoilguy.com/forums/ubb...true#Post343975
4. http://www.bobistheoilguy.com/forums/ubb...true#Post343979
5. http://www.bobistheoilguy.com/forums/ubb...true#Post343981
6. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=343972&page=2
7. http://www.bobistheoilguy.com/forums/ubb...ge=2#Post343989
8. http://www.bobistheoilguy.com/forums/ubb...true#Post343986
9. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1284839#Post1284806
10. http://www.bobistheoilguy.com/forums/ubb...rue#Post1284862
11. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1284839#Post1296303
12. http://www.bobistheoilguy.com/forums/ubb...786#Post1670786
Positive:
Several BITOGer's have suggested that magnets may catch particles which would be too small for the filter to catch. In one thread particles were examined under a microscope showing that what the magnet caught was below the filter's capacity (1). Another mentioned that particles all the way down to 2 microns cause additional wear thus if the magnet catches these it could be helping (2).
Additional, comments mention that some OEM oil plugs contain magnets and that transmissions often have magnets in them suggesting that some manufactures think magnets are a good idea (3). Often a threat will include at least one post which states that it seems like even if it can't be proven that magnets help it seems like it can't hurt so if it improves your comfort level use them (7).
Negative:
There were also plenty of negative comments. In many threads there was at least one skeptic who didn't think magnets would catch particles smaller than the filter element can catch, or that if there are particles are large enough for a magnet to catch it suggests that really serious unusual wear is occurring (5, 6). Additionally, many have suggested that the same wear still occurs and even if iron is lower in UOA it's only because the wear particles are on the magnet and not detectable in the UOA (unfortunately I lost the links for these posts...but there were plenty of them and they can be found using the search feature). In one comments a user referenced an article from Noria's Machinery Lubrication which suggested that the use of magnets may cause particles to be released in a particle cloud, apparently from a bust of flow or jolt...etc, and thus resulting in a clog upstream (4). In the same comment (and in other threads) the concern is raised that this could lead to magnetized particles which could then stick to critical parts of the engine. Probably the most negative comment though was one which stated that in a study conducted over 10 years ago by a fleet operation the use of magnets made virtually no difference in UOA vs a control group that was not using magnents (8).
Techniques:
A few have suggested that placing a magnet on the oil pan might be a good technique (9). However, in the same thread other commented that this is probably a bad plan as particles may remain stuck to the pan even though the magnet is removed before draining the oil. Thus, this technique could lead to years of particles collecting in the same place and possible resulting in a cloud of particles being released sometime in the future. So the recommendation is to place magnets on the oil filter. In almost every thread there is at least one post advocating the use of magnets from old hard drives (10). At least one comment mentions that they last a very long time (at least 8 years) in spite of the high heat conditions. Other comments mention magnets that can be placed inside the return side of the filter, though some BITOGer's are concerned about flow restriction with this (sorry lost the link). Another post mentioned epoxying a magnet to the oil plug and others have mentioned simply purchasing a magnetic drain plug (sorry no link again). Additionally, there are plenty of after market magnets which can be purchased which will attaches to the side or the bottom of the filter. This link provides a pic of what one side mounted magnet caught (11). Of course there are plenty more pics if you search the filter forum for magnet.
Quick Summary:
The pictures posted in the forums clearly show that magnets in oil do catch particles of iron which are in the oil. However, it seems like the only scientific information we have to go with here is the fleet study which indicated that magnets don't really make a difference the actual wear that is occurring. Additionally, the concerns about particle clouds seem like a bit of a deterrent to me. I still have some other concerns such as could additives be trapped by the magnet. I know the additives are not ferrous but I'm aware that there are some other non-ferrous minerals which are attracted to magnets, but I'm not sure which one's they are or if they are used as additives. I've also seen concerns posted about magnets interfering with bypass valves but generally the replies suggest that should not be a problem (12).
Any other thoughts on this topic? I appologise for the length of this post...there was a lot of data out there.
1. http://www.bobistheoilguy.com/forums/ubb...985#Post1611773
2. http://www.bobistheoilguy.com/forums/ubb...287#Post1326372
3. http://www.bobistheoilguy.com/forums/ubb...true#Post343975
4. http://www.bobistheoilguy.com/forums/ubb...true#Post343979
5. http://www.bobistheoilguy.com/forums/ubb...true#Post343981
6. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=343972&page=2
7. http://www.bobistheoilguy.com/forums/ubb...ge=2#Post343989
8. http://www.bobistheoilguy.com/forums/ubb...true#Post343986
9. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1284839#Post1284806
10. http://www.bobistheoilguy.com/forums/ubb...rue#Post1284862
11. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1284839#Post1296303
12. http://www.bobistheoilguy.com/forums/ubb...786#Post1670786