Are Magnetic Oil Drain Plugs Helpful for Long Engine Life

[WVhybrid]

Recently when reviewing some equipment standards for a client, I noticed the requirement for a magnetic filter in the lube oil system. That made me think that a similar treatment of my Volt's lubrication system may pay off. With the high compression ratio of the Volt engine, any piston or ring wear might have serious consequences on performance. I've attached a graphic of the magnetic drain plug that is supposed to fit the Volt.

I have found two types of magnetic treatments for car engines. First is a small magnet on the end of the oil drain plug, and second is a belt-like magnet around the oil filter. I was wondering if anyone would care to comment about the usefulness of either type of magnet. Are the claims I've read about the usefulness of these plugs real? Can they serve to minimize engine wear? The drain plug is not very expensive; Amazon has one for the Volt for less than $10. The magnetic belt that fits around the oil filter seems to be a bit more pricey.

So should I buy a drain plug magnet or an oil filter magnet?

WVhybrid
Red Volt #1715

[Adarondax]

GM designed your engine to last for the life of the car provided you follow recommended maintenance. Good motor oil will keep any iron dust suspended. A magnetic drain plug with a permanently fixed magnet (not a removable magnet!) will tell you how well your oil is working. It's more useful in older cars and could, for instance, demonstrate the superior lubricating ability of synthetic over mineral-based oils. You'll see more gray dust on the magnet with mineral-based oil. At least that was true 10 years ago when I tried it. Considering how little the Volt's engine runs, you may only be checking the magnet every 2 years. If it makes you feel better, get one but I wouldn't worry about it. The magnetic band for the oil filter sounds like a gimmick. Maybe you can use the magnetic drain plug with and without the band to see if it works. Could be a 4 year experiment though.

[Raymondjram]

I tried the magnetic test on the drain plug of my 1995 Buick Regal by gluing a small magnet to the plug tip. After one year, there was nothing on the magnet, so I removed it. I later understood that if the oil and filter were doing their jobs, there should never be any particles on that magnet.

My 1995 Buick Regal uses only Mobil 1 synthetic oil (with once-a-year changes), so the magnet proves that after sixteen years (and only seventeen oil changes) there is almost no metallic wear inside the engine. Using synthetic oil is a much better recommendation than a magnetic oil plug.

Raymond

[Rooster]

A magnetic oil drain plug is just for inspection. In short, you should never see any metal shavings on it. If you do, it means you have engine damage/worn components and need a rebuild.

[WVhybrid]

Thanks for the replies. I think I see your points. Perhaps a magnetic plug would be more useful on my Prius, where the engine runs more often. Two comments about the Volt engine: 1) the oil does not circulate very often, so any dense materials not held up by Brownian motion (about 1 micron and smaller) would tend to settle. 2) There is likely to be a range of particles, perhaps less than 30 microns, that will tend not to be captured by the oil filter.

A thought experiment would probably say that the smaller particles than can pass through the Volt's oil filter can't cause the as much damage as the larger particles (that are captured) can cause. I'm sure there has been a lot of research on this subject, and that engine designers have a good understanding of the subject. To me they are questions I haven't worried about until I bought this wonderful car.

Industrial machines like the specs I was reviewing tend to run continuously for a year or more between oil changes, so magnetic separation may be more important. I doubt I have 25 hours running time on my Volt's engine in the 3 months I've owned it.

WVhybrid

[WVhybrid]

A magnetic oil drain plug is just for inspection. In short, you should never see any metal shavings on it. If you do, it means you have engine damage/worn components and need a rebuild.

Excellent reply. And concise! Now I understand why guys who run antique cars swear by the plugs.

I think I will keep my $10 in my pocket.