How strong a magnet should I ducttape to the oil filter?

[sad-lumina-owner]

apparently a magnet on the oil filter grabs all the bits of metal floating in the oil.

I was thinking

(1) I'd like to try this for a few oil changes.

(2) I'd like to open an oil filter and see if it worked.

(3) I'd like to do it for free/cheap, and not have to buy some overpriced kit.

[CoolasIce]

Search for super strong neodymium magnets. http://www.kjmagnetics.com/proddetail.asp?prod=BY0X08BR

[2.2 Straight six]

It's a gimmick.

An oil filter is just that, a filter. All the magnet does is hold any metal "filings" in the same place. If you don't have the magnet the filter will still catch them. There is zero gain to be had by putting in a magnet.

[shorod]

Wouldn't the same apply to an automatic transmission, yet they still use a magnet in the pan there. Granted, the service interval for a transmission filter is longer than that for engine oil filter.

With a transmission, when you drop the pan to access the filter it's easy to see the magnet and the amount of metal particles on the magnet. With a magnet on the oil filter, one would have to carefully cut open the filter without disturbing the magnet.

I do agree that a magnet on the oil filter is likely not worth the effort unless you plan to run the engine oil for MANY times longer than the vehicle manufacturer recommends. The magnet may collect metal particles along the metal case of the filter that would otherwise collect in the filter media and, over time, reduce filter flow/efficiency. And obviously running an easily replaced (relative to a transmission filter) engine oil filter that long is not recommended.

[KiwiBacon]

In addition.
Magnets only catch iron and steel. It won't help you see aluminium, chrome, bearing materials etc.

[Moppie]

Originally Posted by shorod

Wouldn't the same apply to an automatic transmission, yet they still use a magnet in the pan there. Granted, the service interval for a transmission filter is longer than that for engine oil filter.

A magnet in the pan is different from having a magnet in the filter, as it will separate out iron debri before it reaches the filter.

[MagicRat]

Originally Posted by shorod

Wouldn't the same apply to an automatic transmission, yet they still use a magnet in the pan there.

Transmission filters do not seem to filter out tiny particles. I suspect they need to flow more fluid than an engine oil filter, and do so with less filter surface area, so their filters have larger pores.

Also, many cars use magnetic drain plugs to catch metallic (ferrous) debris.

[shorod]

Originally Posted by Moppie

A magnet in the pan is different from having a magnet in the filter, as it will separate out iron debri before it reaches the filter.

But doesn't the oil flow from the outside of the filter to the center, in which case a magnet around the circumference of the filter could conceptually trap ferrous metals prior to them reaching the filter media?

Granted since the magnet would be on the outside of the metal filter can, the magnet would need to be very strong (such as neodymium) and around the circumference of the filter, as close to the base of the filter as possible. For the cost of a large neodymium magnet that would suit this purpose, it would be less expensive to just change the filter out twice as often probably since if there are enough metallic particles to plug a filter in less than 5000 miles, there isn't much life left in the engine anyway.

-Rod

[j cAT]

Originally Posted by shorod

But doesn't the oil flow from the outside of the filter to the center, in which case a magnet around the circumference of the filter could conceptually trap ferrous metals prior to them reaching the filter media?

Granted since the magnet would be on the outside of the metal filter can, the magnet would need to be very strong (such as neodymium) and around the circumference of the filter, as close to the base of the filter as possible. For the cost of a large neodymium magnet that would suit this purpose, it would be less expensive to just change the filter out twice as often probably since if there are enough metallic particles to plug a filter in less than 5000 miles, there isn't much life left in the engine anyway.

-Rod

as stated the filter captures many types of debris that can be generated/created in the engines lubricating system...


a simple magnetic drain plug is all thats needed....the returned dirty oil gets dumped into the pan ,, this is where the drain plug magnet is best located before it gets pumped into the filter....

the filter should be cut open to determine with all certainty your correct filter change interval...and also if your selected filter is designed properly..these filters are not manufactured equally..


most vehicles require this filter to be replaced at the 5,000mi point max...

Only very small amounts of steel debris will be created if things are going good in your engine ...just a small amount of dust sized particles...this filter magnet will not improve the filters life by any significant amount..


however if it is possible, the use of a heat sink mounted on the oil filter will aid in reducing the oil temp...the reduction of this temp will increase the oil life..

[UncleBob]

IMO, magnets in a tranny pan or magnetic oil drain bolts, are purely for quick verification if things are coming apart

Magnets on an oil filter, pointless.

[partsmgn]

When I re-built a Detroit Diesel engine... it had a magnetic oil pan to trap any metalic particals that were floating in the oil. As far as using a magnet on the oil filter they sell a magnetic pad that clings to the oil pan to trap any particals in your motor. But your filter should trap most of them (besides thats its' job) if you have lots of metal shaving you could have larger problems

[sad-lumina-owner]

Not 100% convinced a magnet on oil filter is useless (depending upon where exactly its placed).

It seems that in some cases, the oil goes to the pan BEFORE heading out to the oil filter... Is this true of ALL cars? and years?

From my original perspective, the oil was pumped up (on some engines) through the rods(?) to the top of the rockers etc. from where it then poured/dripped down through the engine and or entered the crankcase(?), perhaps THEN to the filter then pan, or THEN to the pan and then filter...

Which is it? It makes a big difference, since this would determine where a magnet is best placed, either on the oilpan or the filter.

Also for consideration is the fact that oil filters obviously can either

(1) get clogged, or

(2) deteriorate (rip or start getting holes).

It seems to me that trapping metal filings of any size BEFORE it hits the filter could lengthen the effectiveness of the filter, or prevent it from being damaged/clogged.

So the magnet could provide an 'extra' step of protection for the rest of the engine, wherever it is best placed.

Anyone have a real clue as to actual oil flow in a modern car, particularly a Chevy Lumina 3.4L v6 for instance?

[jonathanwang]

L think the magnet is used to hold the bits of metal,in fact it work as another kind of filter.It work together with the filter and at the same time it can extent the life of the filer.

[2.2 Straight six]

A filter is a serviceable part. It is meant to be replaced before the end of its expected lifespan. This is preventative routing maintenane.

If putting a magnet on an oil filter was that effective, don't you think all the big companies would have done it by now?

[PistonPower]

in the average engine the oil is sucked up from the sump by the oil pump. the pump then pushes the oil through the filter. once the oil is filterd it is ready to lubricate the mooving engine parts, it travels through the crankshaft and all its bearings and the balance shafts then goes up to the head. after lubricating the camshafts it then comes back down to the sump. on its way it might collect small bits of mettal from wearing parts so the best place to have the magnet is in the sump. it is placed there so all the bigger shards of mettal can be collected before the oil travels back through the oil pump where it might do some damage. the sump magnet is not verry big though so its magnetic field will only attract the biggest shards of mettal, the rest has to get filterd out by the filter, but they are so small that they will not cause any damage to the pump. the oil is then "clean" agan and ready to do its job.
its not that hard to do a oil and filter change, check your dipstick, if the oil is dirty its time for a change, your engin will also last alot longer and its not that expensive.