For those wondering if magnetic drain plugs work

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garlicbreadman

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im not science major or anything like that and i was curious to see if a magnetic drain plug can still magnetize metal objects when an engine is at full operating temperature. I heated water to boiling temp(212F which is around the temp oil is when fully warmed up), poured that water in a glass container and stuck a magnet holding a bolt screw and cotter pin in the boiling water. I shook the magnet vigorously in attempt to shake off the metal objects.


I read that a while back that magnets lose their magnetism at a certain temperature(curie temperature??) and this was just to confirm for myself that magnetic drain plugs are effective...since i run one in my engine and transmission. Not all magnets are the same, this magnet happens to be quite strong and the ones in my engine and transmission are even stronger. Theres no way i can replicate the situation inside an engine oil pan, but this is good enough
 
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Works for me. Thanks for posting. I also use magnetic drain plugs in my cars and they collect plenty of stuff to make it worth while for me to use them.
 
Originally Posted By: nixon
Exactly what do they pick up that the filter might miss ? Basically they sit in the back of an oil pan ,and do what ?


Exactly they pick metallic debris below 10um that filters pass through.
 
My wood stove has a magnetic thermometer stuck to its flue pipe. It reads up to 900'F. Instructions say to use included wire to secure it, as if a fire went nuts, as in over 900 ish degrees, magnetism may fail.

I left the wire off, as I'd want to hear the thing crashing to the tile below if I had a chimney fire. I have had a couple close calls with the needle pegged and the magnet has kept its properties.
 
Originally Posted By: Bluestream
Did you test it after 3-4 hours of heat?


no, only for 1-2 minutes.
 
Originally Posted By: friendly_jacek
Originally Posted By: nixon
Exactly what do they pick up that the filter might miss ? Basically they sit in the back of an oil pan ,and do what ?


Exactly they pick metallic debris below 10um that filters pass through.


The beauty of it is that the particles that pass through the filter cause no harm to the engine. That has been well documented...
10.gif
 
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Originally Posted By: Bluestream


The beauty of it is that the particles that pass through the filter cause no harm to the engine. That has been well documented...
10.gif



If so why some people and OEMs bother with bypass filters?
 
I don't think the question with drainplug magnets is whether they'll work at 100C, it's whether they're necessary at all.

The fact that many ATs have magnetic drain plugs should eliminate the question of whether they'll work at temp.
 
Originally Posted By: friendly_jacek
Originally Posted By: Bluestream


The beauty of it is that the particles that pass through the filter cause no harm to the engine. That has been well documented...
10.gif



If so why some people and OEMs bother with bypass filters?


Mainly to allow extended OCI's. On commercial equipment designed for million miles or more, OCI cost and down time adds up pretty quickly.
 
Originally Posted By: KrisZ
Originally Posted By: friendly_jacek
Originally Posted By: Bluestream


The beauty of it is that the particles that pass through the filter cause no harm to the engine. That has been well documented...
10.gif



If so why some people and OEMs bother with bypass filters?


Mainly to allow extended OCI's. On commercial equipment designed for million miles or more, OCI cost and down time adds up pretty quickly.


I thought they also reduced wear, but could be wrong.

Nevertheless, the major utility of magnets is to indicate if abnormal wear happens by looking at the amount and size of debris.
 
Originally Posted By: eljefino
My wood stove has a magnetic thermometer stuck to its flue pipe. It reads up to 900'F. Instructions say to use included wire to secure it, as if a fire went nuts, as in over 900 ish degrees, magnetism may fail.

I left the wire off, as I'd want to hear the thing crashing to the tile below if I had a chimney fire. I have had a couple close calls with the needle pegged and the magnet has kept its properties.

I guess you must have a single wall flue pipe? We have a double wall so I put the thermometer on the stove top and the magnet didn't last too long and we even cooked the bi-metal strip but it used to read 800F often as my wife likes to get the stove hot... Anyways it did take some serious heat to kill it, I think they must last forever in an engine or transmission.
 
I Bought some 1/2 inch magnetic drain plugs a few years ago for 99 cents, and the magnets were quite strong. I installed them in my transfer case on my Ford Explorer. Last time I drained the fluid, I check the drain plug, and it was still magnetized, but very weak from when they were new. It has been installed for 7 years new, and still picks up the odd metal filing so I leave them in
happy2.gif
 
Here's my $45 transmission drain plug collecting a TON of who knows what from my 2007 Honda Civic Si 6 speed. This was a 20,000 mile interval and the plug went in completely clean, obviously.

drainbolt.jpg


drainbolt2.jpg


The same company makes a magnetic drain for the engine as well and here's what it collected during an 8,000 mile OCI in my Civic with a, i assume, high quality Amsoil Ea oil filter...

IMG_0005.jpg


IMG_0004.jpg
 
I currently have Amsoil's best lube in both my 07 Civics. (EX Auto and Si 6speed.)

Shifts much smoother then the Honda oil, esp when the tranny is cold, and it lasts longer because its synthetic
thumbsup2.gif
 
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