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Manufacturers could improve many things if they wanted to but if it cost them an extra penny their not going to.
Magnetic Drain Plug Truly Worth It?
- Thread starter Ang
- Start date
Manufacturers could improve many things if they wanted to but if it cost them an extra penny their not going to.
That's just silly. Why put one on a diff but not the engine?
Installed at the factory on many of my cars are magnetic drain plugs on differentials, and transmissions.
@Ang - I have had a Gold Plug magnetic drain plug on my Mercedes for over 60,000 miles. I’ve got them installed on other vehicles as well. Engine. Transmission. Transfer case.
They are excellent quality.
If yours is not excellent quality, then I suspect either you got a fake, or you should contact them and get a replacement.
I didn't get a fake, It was sold to me by gold plug. And as I mentioned I eventually did, but I haven't checked that one for a QC Issue yet.
I looked at the goop of my drain plug magnet under my microscope and it appears most of the magnetic mass is 1 micron and smaller.
I'm cheap I make my own. Drill out a drain plug with a 1/4'' bit and drop a 6mm rare earth magnet down in the hole with a little bit of rtv.
$6 worth of 6mm rare earth magnets from ebay appears to be easily a lifetime supply.
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Sure, but I was speaking specifically to engines. I'm not sure I've heard of any.
Perhaps we are saying the same thing; if diffs, trans, etc offer benefit, why exclude engine drain plugs?
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I think you can assume that magnetic plugs aren't needed to get the vehicle past the warranty, but after that, it seems many(most?) manufacturers don't seem to care about getting your vehicle up past 150k+? The "Lifetime fill" stuff, is practically assuring your vehicle won't get past 150k without some major repairs...
It would be interesting to see their numbers on why they put a magnet in the transmissions? I guess enough transmissions have enough machining debris left in them, to fail before warranty to pay for a magnet in all of them?
The only way I know of to test the effectiveness of a magnetic engine oil drain plug is just that; do a scientific test. Without data, we are all guessing. My SWAG is, if they were effective, legendary companies like Mercedes and Lexus would use them.
As a perhaps anecdotal test, perhaps BITOG contributors can speak to the results of their magnetic engine drain plugs?
@Astro14 you believe in using quality parts and I am guessing this is over time. Can you speak to your results?
Carlostrece
$100 Site Donor 2025
I've never heard of anyone having a problem with a Gold Plug. I wouldn't worry about its glue. Plus the oil pickup has a screen on it. So the worst that could happen if magnet came loose is it'd stick to that screen. Anyone feel free to correct me if I'm wrong.
The legit purpose of a magnetic drain plug is to show you a sample of the ferrous (iron/steel) particles circulating in your oil so you can see how much (and how big) ferrous (iron/steel) particles are in your motor oil. This gives you an idea of engine health, wear, and a warning if anything is catastrophically shredding metal or breaking.
i.e. - A magnetic drain plug's purpose is to show you if there's a problem.
A drainplug magnet is not big enough to remove signifigant amounts of ferrous particles out of oil.
If you want magnets that are big enough to remove most ferrous particles from your oil... A pair of Filtermag SS will remove almost all ferrous particles from your oil.
Put a pair of Filtermag SS on outside of oil filter. When you change oil move the pair of Filtermag SS to the new oil filter.
In the second photo you see a cut open oil filter can. On the inside of the can you can see the ferrous particles that Filtermag SS captured and kept inside can. Thus removing those ferrous particles from the oil.
The legit purpose of a magnetic drain plug is to show you a sample of the ferrous (iron/steel) particles circulating in your oil so you can see how much (and how big) ferrous (iron/steel) particles are in your motor oil. This gives you an idea of engine health, wear, and a warning if anything is catastrophically shredding metal or breaking.
i.e. - A magnetic drain plug's purpose is to show you if there's a problem.
A drainplug magnet is not big enough to remove signifigant amounts of ferrous particles out of oil.
If you want magnets that are big enough to remove most ferrous particles from your oil... A pair of Filtermag SS will remove almost all ferrous particles from your oil.
Put a pair of Filtermag SS on outside of oil filter. When you change oil move the pair of Filtermag SS to the new oil filter.
In the second photo you see a cut open oil filter can. On the inside of the can you can see the ferrous particles that Filtermag SS captured and kept inside can. Thus removing those ferrous particles from the oil.
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I suspect you are right for modern car engines, that its rare that magnets help significantly? Maybe if you have an engine with a common problem in the valvetrain? Cams that weren't made right, or undersized/wearing timing chains?
I've probably never going to cut open filters to see if there's anything developing that is worrying, but I will look at the drain plug every change, and feel for any grit of significance.
Carlostrece
$100 Site Donor 2025
A pair of Filtermag on oil filter helps quite a lot for removing metal from oil during initial 30K miles breakin period. It's less helpful after that, but still somewhat useful at any mileage, IMO.
A magnetic drain plug is not much help for removing metal from oil, but it does provide visual cues which can be useful for monitoring and diagnoses.
A magnetic drain plug is not much help for removing metal from oil, but it does provide visual cues which can be useful for monitoring and diagnoses.
Carlostrece
$100 Site Donor 2025
I'm guessing it's partly because a motor has an oil filter. A differential does not.
So a differental has more need for a magnet.
The answer is, it is probably not necessary or they would use one. That's my point.
I personally do not know of a vehicle that uses a magnetized engine oil drain plug, but that does not mean none exist.
CleanSump
Site Donor 2026
Honest question. If you saw or believed it was defective in some way, why did you install it?
I've run them in every sump for decades. One went over 300k miles and the magnet didn't "fall off". None have come apart.
I've run them in every sump for decades. One went over 300k miles and the magnet didn't "fall off". None have come apart.
In reality these absurdly expensive $70 for 1 or $110 for 2 Filter magnets would solve the issue of not trusting the magnetic drain plug with the same outcome.
Carlostrece
$100 Site Donor 2025
I look at it this way. A pair of Filtermag SS is a one time expense for the life of my vehicle. They can easily be moved to my next vehicle if it has a similar diameter oil filter. The cost for a pair of Filtermag SS is equal to 8.5 of my oil premium filters.
Engines with under 30K miles shed a lot of ferrous particles of various sizes. After 30K miles an engines sheds less ferrous particles, but still sheds some.
A premium oil filter by itself can remove 99.9% of particles that are smaller than 20-25 microns. A pair of Filtermag SS removes all ferrous particles that are larger than 2 microns and some that are smaller. i.e. - Filtermag is very effective at its job.
Is a pair of Filtermag needed? That depends on how you define needed.
It's not needed to reliably go as far as car warranty covers, which is what car makers care about.
I think Filtermag SS is very helpful to new engines during breakin period, IMO. That's assuming you want engine to last as long as possible. With Filtermag SS in place, I would feel no need to change oil and filter early during engine breakin period. I'd just change oil and filter at a normal 3.5-5K OCI same as I would after breakin period (depending on driving style and climate).
So the pair of Filtermag SS on a new car pays for itself quickly by reducing wear from seed contamination during new engine breakin period, and because you don't need to change oil or filter early to remove ferrous wear particles. Over the 30K engine breakin period, Filtermag more than pays for itself, IMO.
I think Filtermag SS is still somewhat helpful after 30K miles engine breakin period, but not as helpful and certainly not a necessity.
Will Filtermag ever pay for itself if you put it on a high mileage car? It's debateable. It might help, can't hurt.
Which pop culture has taught us via Click comes from the (tiny) schmeckel
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