Ominous Engine Signs? (magnetic sump plug)

[svenedin]

I did my annual engine oil and filter change today. At the last oil change I fitted a "Gold Plug". This is a powerful Neodymium magnet sump plug. 12 months and roughly 3,000 miles since the magnet was installed.

I was quite alarmed by the amount of metal on the magnetic sump plug. Does this seem worrying?

The oil was the usual dirty black. There was no silvery sheen to the oil.

The engine runs well. Compression when last tested a few months ago was normal (150 psi) in all cylinders.

Stephen

IMG_9820.jpeg (1.75 MiB) Viewed 623 times

[philthehill]

If you did not have the magnetic sump plug you would be no wiser and would not worry.
The iron particles could be from any part of the engine.
So long as you have good oil pressure plus good compression and there are no unusual noises I would not be too concerned about the crap on the magnetic sump plug.

[les]

With the standard sump plug, draining the oil over the years is bound to leave sediment on the sump bottom, then when you fit a magnetic plug all those particles over the years are suddenly drawn to the magnet, so you’ve probably got all those years worth on your recently installed magnet !

[svenedin]

Good pleased to hear that! No unusual noises, engine goes fine. I don't have an oil pressure gauge but the oil pressure warning light goes out as soon as the car is started.

Yes, the magnet has probably picked up years of metal from the sump. I did think about dropping the sump and cleaning it out but I didn't have the gaskets and seals at hand. At the next oil change (which I may do early out of caution) I will drop the sump as well and clean it all out.

Stephen

[MikeNash]

I've been running magnets for some 60 years and seen many in aero engines too, and what Les & Phil say above is quite right. In an old engine the first time you take one out it will scare you witless; just be pleased that all the crap is there on the magnet and not everywhere else. Remember that while the oil filter will only collect stuff down about 20 microns the magnet will collect down molecular size and even aluminium particles are attracted 'cos ali is paramagnetic, that is, it's weakly magnetic when in the magnetic field. Of course these particles need to be close to the magnet to be drawn to it, hence that value of more and bigger magnets! Try one in your back axle for a real frightener.

[Chief]

So, magnetise the Purolator collar and I guess you could collect all sorts of metal particles in the filter housing rather than keeping them in the engine

even aluminium particles are attracted 'cos ali is paramagnetic, that is, it's weakly magnetic when in the magnetic field.

I presume the larger the aluminium the reason why it won't stick to magnets? (just remembering the early 90's when can recycling banks became a thing and you got those free testing magnets to check which bank to use for cans).

I was quite alarmed by the amount of metal on the magnetic sump plug.

Does have a nice, almost crystal-like, aesthetic to it though.

[svenedin]

I've been running magnets for some 60 years and seen many in aero engines too, and what Les & Phil say above is quite right. In an old engine the first time you take one out it will scare you witless; just be pleased that all the crap is there on the magnet and not everywhere else. Remember that while the oil filter will only collect stuff down about 20 microns the magnet will collect down molecular size and even aluminium particles are attracted 'cos ali is paramagnetic, that is, it's weakly magnetic when in the magnetic field. Of course these particles need to be close to the magnet to be drawn to it, hence that value of more and bigger magnets! Try one in your back axle for a real frightener.

Phew! Yes I was really rather alarmed! It is a very powerful magnet and actually it was difficult to clean the metal particles of it. As you say, they were extremely fine particles.

I don't have one in the back axle but I do have one in the gearbox. I know that will be alarming when I see it.

I agree with Chief it looks rather beautiful. Like a sort of oily crystal! Perhaps a bit like the living metal in the Terminator films.

Stephen

[oliver90owner]

The next oil change, with a check on the magnet, will surely provide you with far more info than thus far. Most/many modern engines don’t have the sump drain plug removed at oil-change intervals - the old oil is simply pumped out, not drained.

Full-flow oil filtration will collect all particles, that could damage white metal bearings for instance. Well, until the (spin on) filter gets blocked and unfiltered oil is circulated. Not good for oil pumps - and some particles can be generated there as it pumps unfiltered oil….

[svenedin]

The next oil change, with a check on the magnet, will surely provide you with far more info than thus far. Most/many modern engines don’t have the sump drain plug removed at oil-change intervals - the old oil is simply pumped out, not drained.

Full-flow oil filtration will collect all particles, that could damage white metal bearings for instance. Well, until the (spin on) filter gets blocked and unfiltered oil is circulated. Not good for oil pumps - and some particles can be generated there as it pumps unfiltered oil….

Fair enough. I intend to do another oil change considerably earlier than I usually would just for my peace of mind. I also want to drop the sump to see what is lurking in it. I don’t have a spin on filter. I have a Purolator with the blocked filter switch (not that I have ever seen that warning light come on to indicate a blocked filter)

Stephen

[oliver90owner]

Fair enough. I intend to do another oil change considerably earlier than I usually would just for my peace of mind. I also want to drop the sump to see what is lurking in it. I don’t have a spin on filter. I have a Purolator with the blocked filter switch (not that I have ever seen that warning light come on to indicate a blocked filter)

Stephen

It is fairly obvious the spin-on filter comment does not apply to your type of filter. It was included for the benefit of inexperienced readers with vehicles using that type.

Experience re sump contents? If non detergent oils are/have being/been used, there may well will be some sludge. Detergent oils will result in a clean sump - but may not remove all historical deposits. IMO, removal of the sump is a waste of time and effort unless there is a historical risk. A flushing oil is likely a better route to go. Most engines do not need the sump removing unless attending to, or investigating, bottom-end problems.

[les]

Like all things in life, it may not strictly need doing but it’s what gives you peace of mind that counts.

[svenedin]

Fair enough. I intend to do another oil change considerably earlier than I usually would just for my peace of mind. I also want to drop the sump to see what is lurking in it. I don’t have a spin on filter. I have a Purolator with the blocked filter switch (not that I have ever seen that warning light come on to indicate a blocked filter)

Stephen

It is fairly obvious the spin-on filter comment does not apply to your type of filter. It was included for the benefit of inexperienced readers with vehicles using that type.

Experience re sump contents? If non detergent oils are/have being/been used, there may well will be some sludge. Detergent oils will result in a clean sump - but may not remove all historical deposits. IMO, removal of the sump is a waste of time and effort unless there is a historical risk. A flushing oil is likely a better route to go. Most engines do not need the sump removing unless attending to, or investigating, bottom-end problems.

Ok. There is actually a slight leak from the block/sump union so removing the sump was something I was going to do at some point anyway. The engine has run “Castrol Classic” 20/50 for as long as I can remember (a low detergent oil). Back when I was young the engine had whatever oil was on special offer at the time. I was a poor student and the car leaked a lot of oil back then. It effectively was continuously changing its own oil.

At oil change I add an engine flush additive. The instructions say to run the engine at idle for 20 minutes but I often go for a short drive. It does seem to help shift the rubbish so I don't think it's snake oil.

I wasn't being awkward about the type of oil filter Oliver. You would know from other threads that I have retained the original Purolator but I have not mentioned that in this thread so anyone just reading this thread would not be aware.

My Audi S3 has a composite sump and I don't drain from the sump drain. I suck the oil out from the dipstick hole with an oil extractor. I do not know if that leaves rubbish behind as I am not going to take the sump off that car!

It’s years since I have dropped the sump. Last time there was sludge. My car is used frequently but it does not tend to do long journeys. I think this contributes to sludge problems because the oil sometimes does not get to operating temperature.

Stephen

[Bill_qaz]

Have you tried cutting the oil filter element open and inspecting to see if metal particals are circulating or just years of sludge in sump and magnet has picked ferrous bits..

[Peted7202]

After 3000miles/12 months I wouldn't expect oil to be dirty black if previous oil changes were also done regularly.

[svenedin]

After 3000miles/12 months I wouldn't expect oil to be dirty black if previous oil changes were also done regularly.

The black is Molyslip I added to that oil as an experiment. It also had a flushing agent run through prior to the oil change which does shift an awful lot of muck. I probably won't use the Molyslip again as it makes the oil very dark and it is then hard to determine the oil condition.

Stephen

[svenedin]

As I was still a bit worried I did another oil change after about 100 miles. Actually it wasn't an oil change. It was an oil drain, strain and put back.

There was absolutely minimal ultra fine metal on the magnetic filter plug. There was no metal in the drained oil (I filtered it through a strainer funnel).

I thought I'd report back to say that those who said don't worry were absolutely spot on.

Incidentally, if you do use a flushing additive at oil change time it does make the drained engine oil extremely dark from all of the dissolved deposits and varnish. This time of course I did not use a flushing agent as I was re-using the oil given it only has 100 miles on it! I did change the filter though as they are so cheap.

Stephen

[les]

I like your ‘better safe than sorry’ attitude, peace of mind is worth a lot !——— anyone can say ‘that’ll do’ !

[philthehill]

If you want the 'A' Series block internals and the sump to be clean use a high detergent diesel engine oil.
The engine and sump will be clean but the engine oil filter will need changing more regularly.

[svenedin]

If you want the 'A' Series block internals and the sump to be clean use a high detergent diesel engine oil.
The engine and sump will be clean but the engine oil filter will need changing more regularly.

Ok. Some of the "Classic" oils are pretty low on detergent. Castrol Classic is low detergent. Millers Classic Pistoneeze is moderate detergent. This is according to the manufacturers. Some oil websites say the Millers oil is high detergent (https://motorspirit.co.uk/product/mille ... eze-20w50/). I was using Castrol Classic but at the oil change I switched to Millers Classic Pistoneeze because I was quite shocked by the quantity of black muck that the flushing agent shifted (Wynn's engine flush).

I suppose if sludge gets to the point that it blocks oil ways or the oil pick up then this is a serious problem but otherwise does it actually matter?

Stephen

[philthehill]

Better to have the sludge in the oil filter rather than in the rest of the engine.
When I worked in the garage trade we looked after a high annual mileage petrol Hillman Hunter. The engine was filled with diesel engine oil and it was surprising how clean the engine internals were when it was stripped for overhaul.
No sludge was found in any part of the engine and very little component wear experienced either.