First off, I want to say I enjoy all the information exchange through this forum. It has been very helpful and I am preparing for changing the engine oil with 5w-40 Castrol Syntec, K&N cartridge oil filter with OEM housing, bleeding of the brake fluid and spark plugs. My questions to you all are:

Any advantages and/or disadvantages of using the magnetic drain plugs?
Are they effective?
If so, which brand is recommended (LN Engineering, Dimple, etc)?
For the metallurgists - any comments related to magnet strength, magnet material, effectiveness with increase in temperature, compatibility of magnet to aluminum versus steel, etc?

I have seem members installing the LN Engineering drain plug and/or the spin on filter adapter, etc. But I have seen any feedback related to the actual effectiveness of the drain plug - anyone changed your oil and check the deposits on the magnetic drain plug?

So, I either spend another $35 bucks for something that is effective and works or spend it on something else.

Let the debate begin!

 

I don't believe that there is any practical way to measure the value of the magnetic plugs as you note. Doing it scientifically would require two cars (one with and one w/o) driving the same course for a significant amount of miles (say 25K to 50K) and then measuring the wear on parts after disassembling the engines.
OTOH, qualitatively they seem to be a good thing to add. All one needs to do is open up the magnetic drain plug after 3-6 months, or better yet crack open a spin-on filter that is wrapped with one of those magnetic blankets and you can see a load of particles (more with a new car) that are trapped rather than being circulated in the system. Whether they actually contribute to wear if not trapped seems likely, although that really would require the scientific testing I cite above.
Or perhaps some expert on the site has done some more practical form of measuring.
For the psychic value versus the cost, I would certainly add the parts.

 

I think a filter that is wrapped with a magnetic blanket is a great idea. What concerns me about the magnetic plug is that it will hold a certain amount of particles and then some of them break free all at once. We have all seen that happen when playing with magnets or with those magnet face doddle games. Without the magnetic plug they would have been trapped in the filter but for the really small micron size particles.

P.S. I have magnetic plug on my non-filtered riding lawn mower. If I check the oil plug before it's started it has a certain amount particles. Check it again after it's warmed up it has less. Check it again it has more & check it the 4th time it has less. My mower is no Porsche but the magnetic plug looks the same.

This is a question to ask "MythBuster".

 

I would think that adding a magnet to the oil filter would be more effective. How powerful is the drain plug magnet? Maybe a few inches away the magnetic properties are so weak there is no particle attraction. At least with the oil filter you have a location where all the oil has to travel to and from, vice what amount/volume happens to be in the pan at any given moment.

 

If there was a big benefit, the factory would have fitted the car with one out of the production line.

I don't buy that the designers and business analysts needed to cut the price by $5 or are purposely screwing the owners into premature engine destruction. But thats just me.

 

Thanks for the replies. Through additional conversation with engine builders, it seems to be an item that can't hurt and may give insight into the engine, keeping in mind that it would only show ferrous metal. These magnetic plugs are much better used for transmissions were the gear shavings would collect - that would explain why many manufacturers add that to the transmission drain bolts.

 

I recall many engines that have magnetic drain plugs. In my old '72 911T both the oil tank and the engine sump had MDP's. I rebuilt the engine soon after the purchase and drove / maintained the car for over 200K miles and always found ring fuzz on the magnets. The size of the particles were very small and keeping them on the magnet rather running them through the scavenge pump to the filter was desirable in my opinion. The filter is only efficient to 30 microns, anything smaller flies through the filter and into the oil tank. Then the oil supply pump picks up the oil and the particles that are suspended in the oil causing wear in the oil pump and into the engine bearings and other sliding parts. Adding a magnetic sleeve to the oil filter may aid the magnetic drain plugs. Maybe the oil filter manufacturers should put a magnet strip inside the filter?

 

Where do they sell this product?

 

This may work if you have the metal spin-on filter:
http://www.ridermagazine.com/output.cfm?id=1743715

 

i actually recently had a first hand experience recently on an advantage of a magnetic oil drain bolt -- we run a ITA class Integra and we run the magnetic drain plugs in both the transmission and oil pan. during a recent oil change we found what looked like the leftovers of a small spring -- it took us a while to figure out exactly what it was but turned out to be the spring from the top of a valve stem seal -- pulled the valve cover and found 4 of them in total actually missing, this was all in a freshly built engine so it aided us in finding the problem before it turned into possibly something bigger

any little information (such as finding random metal on your oil drain plug) is better than no information as far as i am concerned