Magnetic Drain Plug In New Engine

[RayCJ]

Hi...

The vehicle is a new 2018 Mazda 3, 2.5L purchased late last August. At roughly 3000 miles, the oil was changed to Milesyn synthetic 0/20 and filter replaced with a Fram UG 6607. An aftermarket magnetic drain plug was also installed. The vehicle was driven all winter and oil was in service for 5100 miles (vehicle now has about 8k miles). Today, the oil & filter were changed just as before.

Here are photos of the drain plug as it came out after 5100 miles and another showing the collected residue wiped onto a paper towel.

I'm quite pleased... There's nothing really to see here... basically no residue and no large particles at all. Engine design, components, materials etc have come a long way!

Stay tuned to the Oil Filter thread as I did a C&P and will post there next. An oil sample was also taken and UOA will be posted when results arrive.

Ray

 

[miden851]

I have magnetic drain plug on my both cars as well; they both look just as the same at oil change interval @5k;

Honda appears to have noticably a stronger magnetic plug

 

[RayCJ]

Originally Posted by miden851
I have magnetic drain plug on my both cars as well; they both look just as the same at oil change interval @5k;

Honda appears to have noticably a stronger magnetic plug


This is an after-market plug. It's a neodymium magnet. I have no idea what the true lift weight strength is but, it easily lifted a full size swivel-head 3/8" ratchet.


Ray

 

[harry j]

Check into the Dimple magnetic oil drain plug. very powerful

 

[nobb]

I bought one of those eBay magnetic drain plugs and didn't like that the little magnet chips/breaks off easily.

 

[Fifty150]

I buy from Gold Plug.

 

[RayCJ]

FYI: The Curie temperature of neodymium magnets varies dramatically with shape. Given the same density, long cylindrical magnets have much higher Curie temps than flat/pancake ones by significant amounts. A short pancake N42 magnet might have a Curie temp of 80C while a cylindrical one that is longer than its diameter can go 2, 3 or 4 times higher.

Here's a description and calculator:

https://www.kjmagnetics.com/blog.asp?p=temperature-and-neodymium-magnets


Ray

 

[Astro14]

Gold Plug makes a quality aftermarket drain plug.

Works well in the MB.

Put one in the Tundra, but haven't yet changed the oil.

 

[4WD]

That's the brand I trust … and there's some out there NOT to trust …

 

[Sam_Julier]

Gold Plug or Dimple are excellent. I run them in the oil and differentials. And the Dimple Black Hole disc magnets on the side of the remote AT filter.

 

[Linctex]

Originally Posted by RayCJ
A short pancake N42 magnet might have a Curie temp of 80C while a cylindrical one that is longer than its diameter can go 2, 3 or 4 times higher.


That is interesting.

I have never had an issue - - maybe my oil doesn't get too terribly hot, but I ABSOLUTLE GUARANTEE it gets over 100ºC with regularity!!

I do this to all of my spin on filters

Originally Posted by Linctex

Engine seems to be very clean inside.
15,473 total miles on this filter over 2 oil change intervals.
2008 Ford F-150 4.6 with 145,712 miles
Magnets are 8mm N50 neodymium
Oil was "American XT" (Warren) 5W-30 Syn-Blend on clearance from a local Family Dollar that closed its doors.

.
.

 

[dailydriver]

Originally Posted by harry j
Check into the Dimple magnetic oil drain plug. very powerful


I use these as well in BOTH the oil sump and the transaxle drain.

They claim to use the most powerful neodymium magnets possible, but who knows.

 

[RayCJ]

Originally Posted by dailydriver
Originally Posted by harry j
Check into the Dimple magnetic oil drain plug. very powerful


I use these as well in BOTH the oil sump and the transaxle drain.

They claim to use the most powerful neodymium magnets possible, but who knows.

Based on what I already knew and some additional reading at lunchtime, here's some info...

All magnets are temperature sensitive and typically lose strength as temperature increases. Also, magnets have a critical "Curie" temperature where they lose all strength and do not regain it once cooled. Depending on how high the temp goes while still below the Curie temp, a magnet might not regain 100% of its strength when it cools down. This implies a max operating temperature and critical (point of no return) Curie temperature.

A neodymium magnet (N-type) has a max operating temperature of 176F and critical temperature of 590F. Once heated beyond 176 (but less than 590) it will permanently lose some of it's strength and the amount it loses depends heavily on the geometry of the magnet and initial strength. It will now stay at it's new level of strength assuming it never reaches a higher peak temperature. Cylindrical magnets that are longer than their diameter will have higher strength than other configurations (there are some caveats to this related to the polarity of the magnet WRT the physical configuration).

Anyhow, there are other types of neodymium magnets that have higher operating and critical temperatures but, typically have lower initial characteristic strengths. So, it's a double-edged sword. Other types are N, NM, NH and others. They are different alloys.

I looked at some of the specialty sellers of magnetic plugs and my "slippery language alarm bell" is ringing loud and clear. One place specifically states they use 300+ degree operating temp material and cite specific strengths and another talks about magnetic phenomenon and goes on to say their magnets are strong enough to do the job.

The way I see it, if you installed a magnet, check it at your next OC to see how much weight it can lift. For example, in my case, it easily lifted a full size Snap-on flex head 3/8" ratchet. I remember doing the same test before I installed and used it. Given this, it may (or maybe not) have suffered some permanent loss -but so what, it's more than plenty strong to do the job it's supposed to. Depending on how it's designed, either type will do the job -and will do it much better than any traditional soft iron magnet.

Have fun...

Ray

 

[dailydriver]

^^^THANKS for that info!

I will try that 'test' the next time the Dimple oil sump drain plug is out next month for the summer/'rally working' OCI.

(It picked up a LARGE size Crescent Wrench with ease when it was new, BTW.)