Buying Magnets for Automotive Use?

SR77 · Mar 4, 2010

Hello, I want to buy some magnets to put near the drain plug on my oil pan, trans plug and differential plug. I thought I could place a magnet on the outside next to these drain plugs and then when its time to change the fluid I would remove the magnet and the particles will get washed out with the fluid.

I have a few questions though for those of you who have done this or have a knowledge of magnets:

1) How strong(lbs.) a magnet is needed to be strong enough to hold the particles from the ouside of these cases (oil pan, trans case & diff. case). I saw a website that sells magents (http://www.magnet4less.com/) that lists the pull force of each magnet which I saw all the way up to to 15 lbs. What pull force would I need when placing these magents on the outside of these cases?

2) Is there a certain pull force that you shouldn't go above when using them on automotives so it doesn't affect any electical components, etc.? Or is there a certain distance these magnets should be kept from any electrical, computer devices?

3) I read on one magnet site where Neodymium magnets will lose their magnetic properties if heated above 175° F. If this is true will these magnets be helpful for automotive use or will they quickly become deteriorated? What kind of magnets does the Filtermag use, I would hate to spend that kind of money on one for it to lose its magent properties soon after?

thanks for the help,

simple_gifts · Mar 4, 2010

A lot of people just use a magnet from a failed hard drive. Strong and free.

demarpaint · Mar 4, 2010

I use a Klear Force magnet on the dome of my oil filter, others use Magnets from a PC hard drive. I really don't have the answers for your technical questions. I will however say this, which BTW is based on opinion.

I WOULD NOT PLACE A MAGNET AT THE BOTTOM OF MY OIL PAN, in hopes that when I remove the magnet and drain the oil the metal will wash out. Those ferrous metal particles will become magnetized and probably stick to the pan, so in time they will get recalculated through the engine. A magnetized drain plug works because it is removed and cleaned. A filter magnet works because the metal is trapped in the filter and removed. A transmission pan magnet works because the pan is removed and cleaned. I would not use your method. JMO

hate2work · Mar 4, 2010

I agree with the painter, don't put a magnet on the outside of your drain pan.

Try this place, I'll bet they have a magnetic drain plug that fits your rig.

http://www.magneticdrainplug.com/

Blokey · Mar 4, 2010

Also keep in mind most if not all newer cars have aluminum oil pans - the magnet won't "stick".

bigmike · Mar 4, 2010

This has been discussed before. Beaten to death.

bepperb · Mar 4, 2010

1. As strong as you can reasonably get. Hard drive magnets are strong, but they are small. Probably 10 lbs in a magnet the size of a quarter.

2. Doubtful.

3. The hard drive magnets are Neodymium, and they haven't fallen off yet.

Really, I put them on the filter, and the residue they collect doesn't just wash off. It's so fine, it's more like a stain than crumbs.

This borders on witch doctory, but if you have a nerd who can spot you a useless hard drive it's free.

XS650 · Mar 4, 2010

Originally Posted By: SR77

3) I read on one magnet site where Neodymium magnets will lose their magnetic properties if heated above 175° F.

Noedymium magnets start to weaken at about 175F depending on what grade they are. They don't lose all their strength until they get considerably hotter. I don't know how time works into the equation, but regular Neodymium magnets seems to work OK around oil filters.

If you want to learn more, Google "curie point" neodymium magnets. Curie point is the temperature at which a magnet becomes non-magnetic.

oilboy123 · Mar 8, 2010

Sonicar toothbrushes have little magnets that are strong. They are replaced about every three months. I save them for misc uses.

severach · Mar 8, 2010

I buy el-cheapo button magnets off eBay and put them where they are immersed in the oil. One gets epoxied to the end of the drain plug. That's a $30 value for about $0.25. Then for $1 more I place a few of them around the inlet of the oil filter. I check the clearance to ensure they don't get crushed or block the flow and use larger magnets than the filter supply holes so they can't go through. I've never had a magnet corrode, break, or move.

I get a lot more dust than any of the pictures I saw where the magnets are attached to the outside. At these prices it doesn't matter if they work or not and you're not out much if the next quick lube monkey throws them away.

Neodymium is way stronger than needed to be effective so a weakening magnetic field is not a problem. Look at the cheapie magnets that are in automatic transmissions. These are no stronger than refrigerator magnets but they catch a lot of material in a short time. I took a pan back off a week later and was amazed how much fuzz had collected in that short of time. I estimate the magnet was already almost at 1/3 carrying capacity.

Trans and differential probably already have magnets. Anything you add will be too small and might get you to thinking you don't need to pull the covers to service them and clean the magnets.

Buying Magnets for Automotive Use?

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