Magnetic drain plugs

For regular oil changes; NOT SO MUCH benefit, because of the filter and the frequent oil change.

However, the transaxle can do for a magnetic drain plug, which Toyota eliminated in all Gen III Prius models.

Photos of magnetic drain plugs removed from Gen II magnetic drain plugs show a lot of steel and iron particles stuck to them.

 

I've found that, while the engine oil drain plug captures some particles, it is not very much.

 

Back in the day when I drove a '71 Beetle around, the factory-issued magnetic drain plug did catch a fair number of iron filings. Note, however, that this was a car without an oil filter. (And required oil changes every 3,000 miles, in the manual, not made up by some dealer with $PROFITS on their mind.)

KBeck

 

Exactly; the transaxle has NO filter or screen.

 

If your drain-plug magnet is collecting metal filings, it's not doing you much of a favor, considering what else is going on in your engine and transmission to be creating them.

 

Magnetic drain plugs come under the "cheap insurance" category. Every commercial engine, transmission and axle I deal with at work has them. They do no harm, and can keep the nasty stuff from circulating around. Every mechanical device wears if it is used. The idea is to make sure that the wear happens as slowly as possible.

Bill the Engineer

 

Due to the long service life of fluid in transmissions and transaxles, a magnet in the pan or in the drain plug is a cheap effective option.

Every Japanese car that I have owned since 1987 had a small five cent ceramic magnet in the pan.

When examined, they had iron or steel particles in it.

Particles in the fluid acts as an abrasive on the metal gears and modifies friction on the clutches.

 

Provided the drain plug itself is magnetic, a neodymium "button" magnet stuck to it should work. I can buy those locally here for less than a buck apiece. No need to special order anything in that case.

 

In the case of the oil pan drain plug, the plug itself must be bored for the magnet and the magnet be affixed securely to the plug.

If not, the magnet might be attracted to the steel oil pan and come off inside the oil pan in the installation and removal process.

 

In the case of water cooled Porsche engines up to and including 2008, the intermediate timing gear bearing often fails and releases steel particles into the engine.

This is one case, where a magnetic drain plug might help detect the early precursor to engine failure.

 

Since the actual plug is bored out (then the magnet is placed inside that hole) the plug body is weaker than a normal solid oil drain screw. I did break one of the magnetic drain screws in the oil pan. Luckily once I pulled the magnet out of the part left in the oil pan- it provided an ideal hole for the EZ-Out and I was able to back out the broken part easily.
So, just be careful not to over tighten the magnetic drain screws- they can't take torque like a solid OEM steel drain plug.

 

The solid M12x1.25 mild steel drain plug on a Prius oil pan has a proof load on about 12,000 pounds.

Boring a 1/4 inch hole about 1/4 inch deep into the may degrades it to 6,000 or 8,000 pounds with at least another 1/2 inch of the threaded part remaining at full strength.

28 ft. lbs. is the specified torque for the drain plug.

Too many inexperience individuals working on cars know how easily this value is reached with a wrench.

Material strength follows Hooke's Law. Stress is proportional to strain. Exceed the yield strength and the material fractures.

Over tightening a bolt does NOT affect a more secure fitment.

Experienced mechanics learn that early in their careers.