Magnetic oil drain plugs?

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Mrheat

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Hello all,
I know that magnetic transmission drain plugs are common. Are magnetic oil drain plugs worth while? Are common trace metals found in used oil magnetic? Thanks.
 
My mom has a magnetic drain plug on her Malibu and you do find a good amount of fine metallic debris on it. I can't really say if it would make any difference in engine life though.
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Ferrous metals are usually magnetic but non ferrous are not. There are combinations of both in a modern engine.
Even if you collect some iron on the magnet it would seem beneficial. At worst it won't cause any damage.
I wonder if using a magnetic plug could skew a UOA? Hmmm...
 
Youll hear a lot of opinions.

Magnetic drain plugs used to be OE equipment on a lot of vehicles, but less and less have them, IMO because of the 35c cost of the small magnet, and the 3c cost of installing it onto a plug. 38c times millions of vehicles is something that is scrapped because its utility may or may not be there anyway.

MB hasnt used magnetic plugs as far as I can tell, ever. And they have historically been light years ahead in terms of their engineering. Honda is another good engine company that from what I can tell doesnt use them.

That said, put one into any engine, and guess what youll see on it???

Transmissions, etc. use them as a means of supplementing marginal to no filtration in a fluid where the replacement rate is very seldom.

IMO, they are useful. I install them into all of our vehicles, what can it hurt, besides $3.49?

JMH
 
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very little oil comes in contact with the oil drain lug. A magnet can't pull minute particles of iron from the oil unless it's right next to it. you would be better off buying some rare-earth magnets and putting them on your oil filter.
 
Originally Posted By: Rabbler
Ferrous metals are usually magnetic but non ferrous are not. There are combinations of both in a modern engine.
Even if you collect some iron on the magnet it would seem beneficial. At worst it won't cause any damage.
I wonder if using a magnetic plug could skew a UOA? Hmmm...
Precisely what I have wondered for some time. The same also goes for by-pass filter systems.

What I do is take the little powerful magnets off of old sonicare tooth brushes - splotch a little glob of RTV on the new oil filter to keep them is place. I use 2 of the little mags for a bit more magnetic pull. Less than 2 minutes of work for your no cost filter mag.
 
my '98 Z28 came with a magnetic plug. I always make a point to clean the magnet, and when the car was newer, it picked up a fair amount of small iron particles. Like a little black cotton swab. Now that it's got 180K miles, I hardly see any at all.

Why GM used the magnetic plug while others did't is a mystery. It may not help, but it certainly couldn't hoit!
 
I believe in magnetic drain plugs and use them in every car I have. Engine and transmission. There is usually a silver metallic paste on the magnet (neodymium) at oil change time, It has a very fine consistancy. I have toyed with the idea of having it analyzed, but while anal about my oil and filters, just not that anal .....yet:)

I agree that a powerful magnetic set up on the filter is a good idea, It's just that I want to see what is being trapped without filter surgery.
 
Originally Posted By: Loobed
very little oil comes in contact with the oil drain lug. A magnet can't pull minute particles of iron from the oil unless it's right next to it. you would be better off buying some rare-earth magnets and putting them on your oil filter.


Might help a lot more, but doesnt work for all apps.

Given how much gunk can be found on a mag plug in an engine, trans and diff, seems that enough oil gets in contact...

JMH
 
My 02 LS1 has a magnet on the oil pan bolt and its always covered by a fine amount of metallic material. When I build my boat motors I always add 4 large magnets to the bottom of the oil pan as it can't hurt. I also add them beside the oil drainback holes in the cylinder heads. I've torn down 2 motors with the magnets in the pan and heads and its suprising how little material is on them. I still do it as it can't hurt.

I also add magnets to the differential covers on both my SS and Jeep TJ and man are they covered! It looks as if they have grown hair.
 
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I've always believed it's more useful as a tool for fleet managers to indicate when something is going horribly wrong with one of their engines, rather than to filter contaminants.
 
Originally Posted By: Loobed
very little oil comes in contact with the oil drain lug. A magnet can't pull minute particles of iron from the oil unless it's right next to it. you would be better off buying some rare-earth magnets and putting them on your oil filter.


Aren't most oil filter shells made from steel? If so, I don't believe much of the magnetic force from the magnet will actually make it through the filter wall.
 
Originally Posted By: bprimerano
Aren't most oil filter shells made from steel? If so, I don't believe much of the magnetic force from the magnet will actually make it through the filter wall.


Yep. To be reasonably effective, the magnet needs to be in direct contact with the fluid, or separated from the fluid by a thin non-magnetic surface.

Mounting them to an aluminum oil pan might work, but the particles would remain in the pan indefinitely and wouldn't be removed during an oil change (though hopefully they would remained "trapped" by the magnet). The oil pan would need to be removed to thoroughly clean the attracted particles from the engine.

It might be worthwhile to glue a magnet on the side of a GM Ecotec oil filter cavity. The attracted particles could be removed during an oil change when the oil filter is removed. That's assuming that the wall thickness is such that the magnetic field remains strong enough inside the cavity.
 
I use magnetic drain plug, a magnet inside the oil filter (MagnaGuard), and a FilterMag on outside of oil filter. All three pick up debris.
 
Originally Posted By: JAG
I use magnetic drain plug, a magnet inside the oil filter (MagnaGuard), and a FilterMag on outside of oil filter. All three pick up debris.


Yes, Ive had this experience with many of our fleet vehicles but we do not use any internal magnets.
 
My 1985 Porsche 911 has two on the engine, sump/tank, and one on transmission.

On the transmission plug I found bits of gear teeth and a dark moly-like paste. On the engine I find the dark moly-like paste also. Not much on the engine since I clean them more often.

Most unusual. This weekend I changed oil at 5700 miles and found white moly-like paste on the tank drain plug. I have seen slight condensation in the filler cap so I assume that's the reason but I don't know why it would be on the tank drain plug unless it's heavier than the oil.

????

So I like them but just as more info.
 
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