Magnetic Drain Sump Oil Plug

[BigKriss]

Hi guys, is anyone on here running one of these with any comments to add?

Cheers

LInk: http://cgi.ebay.com.au/Magnetic-Drain-Sump-Oil-Plug-BMW-E34-E39-E60-E32-E38_W0QQitemZ170154242233QQcmdZViewItemQQptZAU_Car _Parts_Accessories?hash=item279dfbb0b9&_trksid=p3286.c0.m14

[Ross]

It can't hurt anything.
Examining it at the oil changes will give you a "heads up" if certain parts are wearing. Bearing material won't be held by it so you'll need to tear open oil filters to check for that.

[genphreak]

Actually it can.

Engineers have two schools of thought on them, which is why they come on some some cars and not others. I think that they generally work with transmissions, but importantly the placement of the magnet is a part of the sump design, not (or at least seldomly) fitted to an sump plug.

The case for: Metal is drawn to the magnet and can be removed (and seen) easily.

The case against: Metal particles in the oil that rush past the magnet are actually magnetised by it. (velocityxfield)=a certain amount of charge is imparted.

The oil, as it rushes in and around other engine parts, loses the particles in places where they would normally not linger. Documented examples are conrods, rings and some places where weight is not desirable- however the danger is that the charge builds up with the particles and attracts more particles. chunks come off and end up causing wear in places you don't want, and the cycle goes on and on, thousands of times every time you drive.

In the case of an engine rather than a trans, the environment is much harsher and heat and vibration, pressures, etc are highly volatile, so finding a place where oil flow is controllably consistent is harder. I think that is why engine's tend not to have them.

If the people at the factory worked out it was better not to, my punt is that they'd be right. With a BMW, it is hardly (all) about cost.

[Ross]

That's an interesting case against.
The theory makes sense but in pratice a condition resulting in enough free metal particles to be a weight concern if collected somewhere or to break off in chuncks would have manifested itself in other more obvious ways.

[genphreak]

That's an interesting case against.
The theory makes sense but in pratice a condition resulting in enough free metal particles to be a weight concern if collected somewhere or to break off in chuncks would have manifested itself in other more obvious ways. Agreed I don't think that in a street engine it can't really be a problem...