There's another saying that if your oil is clear,  it isn't doing its job in suspending contaminants.

My guess also,  is after 48 hours the contaminants in the oil sink to the bottom and stay suspended there leaving a cleaner oil as shown.

Ultimately,  it's all guesswork.

The best and proper way is still a UOA. bar none,  the end.

Your eyes definitely cannot see metal particles and those you can see are beyond spectrometer that UOA uses and that's actually prompt for concerns.

I dripped EO on toilet paper, haha.
Here's the result.

Both are the same oil,  Sir.
It's the same oil drip.
One picture was taken instantly after dripping on paper. After 48hrs took another picture (of the same sample).
From beginning till the end there is only one sample.

Thanks for the clarification.

I'm still curious though, how did the visually visible contaminants went missing after 48 hours? Dried and evaporated into the thin air?

There's another saying that if your oil is clear,  it isn't doing its job in suspending contaminants.

My guess also,  is after 48 hours the contaminants in the oil sink to the bottom and stay suspended there leaving a cleaner oil as shown.

Ultimately,  it's all guesswork.

The best and proper way is still a UOA. bar none,  the end.

Your eyes definitely cannot see metal particles and those you can see are beyond spectrometer that UOA uses and that's actually prompt for concerns.

my guess is there wasn't any visible contaminant in the b4 pic.... the so-called contaminants are uneven spots on the toilet paper temporarily holding a minute amount of used oil, hence visibly darker and mistakenly interpreted as contaminants.

on 2nd pic, the oil spreaded/blotted over the paper over time so cant "see" the contaminants anymore.

my guess is there wasn't any visible contaminant in the b4 pic.... the so-called contaminants are uneven spots on the toilet paper temporarily holding a minute amount of used oil, hence visibly darker and mistakenly interpreted as contaminants.

on 2nd pic, the oil spreaded/blotted over the paper over time so cant "see" the contaminants anymore.

Perhaps chemistry should do another try, this time on a proper base to find out haha.

Edit: I have done spot test as well before on tissue and toilet papers but the unevenness observed was in patches rather than dots lol.

Waooooooooooooo .......
fantastic blotter spot at 10600 km you have, Chemistry.
Great combination of Duron 10W30 oil and this engine at 281000 km.
You could've gone on extending OCI further, IMHO.
Btw, care to share the engine/car model with us here ?

Edit:There is simply too heavy a dose of 'myths' on oils in lowyat, IMHO.
Edit2:Without chromatography laboratory paper, it's appropriate to use thick name card/printer paper/letter head etc. for relative comparisons.

Nissan AD Resort Y10, engine GA16 carburetor.
At hand now I have some bank statement white papers, i shall use the blank side for BST later.

Bank/Telco statements are good enough for our purpose,
no need wasting money go buy costly 'chromatography papers' from gwailo countries and start bragging here how good is 'chromatography papers' over bank statement papers bla... bla.... bla...
and condemning the use of 'sub standard' bank statement papers in lowyat............
leading to rubbish/guessing/tak bolih pakai results bla .... bla ... bla....

Btw, do show both the 0-0.5 hrs Blot spot AND the 48 hrs Blot spot to debunk some of the above ............rxxxxxh statements!

I haven't heard an expert suggest that in a long time. In those days of carburetors perhaps it still made sense, but how many of those are still around? All modern cars don't need to be warmed up, and shouldn't be warmed up by idling.

I believe my Xsara was always serviced every 20k or 25k, using normal oil, and up until 150k there was no issue. I did end up having a leaking head gasket, but is that related to the engine oil? From what I know that particular engine is rather tough, except for the head gasket. (Fortunately on that engine it's relatively cheap to fix).

I don't know of any higher engine failure rate, and you can find hundreds of Mercedes for sale that have 500000 km or more on the clock.

But I'm not aware of any statistics about engine defects... maybe it's worse than in Malaysia, maybe it isn't.

How to do the blotter test? Can I use normal printing paper? Like 80g, and relatively fine? Just take out the dipstick and let it drop onto the paper? I have one week to do it... oil change is coming up at the end of the month.

Noted that.
Will post here once completed.

I do agree on the oil doing it's part as a part time cleaner for the engine however i'll say the color of the oil will be a more appropriate marker as the gauge, don't u think so? With that being said, isn't the oil filter supposed to filter the contaminants down to 5 or 10 microns(human hair is 45-70 micron)?

Since the oil filter is present and doing the filtration, how can the visually visible contaminants still present in oil dip? A clear indicator that the engine is mighty dirty or just the oil filter/oil is way due for replacement or both.

Don't get me wrong i also do agree that UOA is the proper mean to gauge the properties of the oil though.

In the end all guesswork.

And if you say its supposed to filter that low micron, your eyes also can't see them how do you determine the darker color is contaminant and is not deteriorated oil?

And even even I mention deteriorated oil,  how deteriorated do you know it is?  You cant gauge viscosity properly nor can you check flash point or insolubles.

My oil samples are way darker than that due to rough /high stress /track usage and yet UOA turn out fine.

Logic here: if your oil filter is so good,  you also don't need to oil change and supposedly all your drained oil would look damn nice right?  (assuming you use good oil)

And again,  all I posted here,  would all be estimates /guesswork without a proper UOA

I would rate Zeng's spot photo as very good. The oil spot is more or less uniform so my guess is this oil has not massively oxidised which after just 6500 miles is sort of what I'd expect. There are no signs of the infamous inner 'black spot' which says your oil is beyond simply oxidising and is now actively condensing/polymerisating and dumping out insolube sludge.

Do be aware that you might need to wait a long time for a proper 'black spot' and if you do get to that point, you will wish that you hadn't. Oil oxidation, especially 'in-engine' oxidation is very chemically complex. I don't profess to understand it and I would be very wary of anyone from the industry that said they did. However there are certain phases that you can point to..

1) the additive depletion phase. In this phase the oxidation is inhibited. TBN is depleted and the other AOs in the oil are mopping up free-radicals. The oil will darken but not all of this darkening is due to oxidation. The oil is picking up wear metals and black gunk from partially burnt fuel (and any oil that's gone through the PCV system and has been burnt). During this phase, the oil's viscosity will be relatively unchanged.

2) the uncontrolled TAN rise phase. Although not strictly correct, you can imagine this phase starting when most of the detergent related TBN has gone. Base oils are oxidising into carboxylic acids. You might also see more take up of wear metals into the oil during this phase. In this phase the rate of oxidation is still essentially being held back by the supplementary AO's in the oil. The viscosity of the oil in starting very slowly to increase as these supplementary AO's deplete but is still reasonable.

3) the horrible phase! This is the phase where everything very quickly goes to cock. TBN is virtually zero, TAN is heading past 10. The oil is now getting very black. Viscosity is increasing exponentially as various bits of the oil start polymerising and taking part in condensation reactions to make very big molecules. Once these hit the solubility limits of the oil, they start plopping out of solution as sludge. This is when you get 'black spot' on the blotter test. Oh and you'll start seeing very bad metal attack.

My guess is that your Quartz oil is in Phase 1. As often as not, oil is thrown away in Phase 1. The oil can be very happy in Phase 2 and the phase can last a long time especially if you're driving gently for long trips. The big problem is Phase 3 is very difficult to predict and it can all go from okay-ish to dire very quickly which is why it's best to err on the side of caution for OCI's.

There is no need to get agitated. I never claimed that "my oil filter" is that good. Also didn't claim viscosity of the oil can be determined through visual inspection nor flash point or any else. Just pointing out that the fact on how an oil filter can filter accordingly as per what was stated. Taking no credit here nor deserve any. Also what I state by gauging the condition of the oil is also based on my point of view that it is absolutely not practical for me and I believe the majority here to get a UOA analysis done during OCI. So I'll just based on the typical recommended mileage aside from color of the oil and buttfeel to know when and at what mileage an oil change is required. But again that's just me.

Interpreting blotter tests is on the same scientific level as reading tea leaves; you can end up convincing yourself of things that aren't really there.