Anecdotal comparison between Euro PCMO and conventional HDEO

Nov 20, 2021
Ontario, Canada
Have some filter media photos from two OCIs with very similar mileage/time/usage but different oils used. Posting in the Euro forum as it seems rather common for new members such as myself to wonder about the use of Euro approved PCMO vs HDEO in old engines.
I realise this is not evidence of any particular base oil or additive being superior to another, I'm mostly just curious about any similar/dissimilar observations others have made.

BMW M20B25, 260k km.
No sludge but a healthy amount of varnish visible under valve cover. As far as I know, the previous owner's mechanic who took care of the car for 20 years prior to my purchase used fairly common conventional oils such as Castrol GTX.

Both OCI using Mann W719/15, very similar city/highway mileage split.

1. 2189km, 183 days - Motomaster Diesel Conventional 15W40 (probably related to Rotella T4)
2. 2137km, 198 days - Motomaster Synthetic 5W40 (probably related to Platinum Euro)

Just FYI for members who don't live in Canada, Motomaster is a store branded oil that claims to be Shell based (can't remember the exact wording).

I was personally surprised to find how much more had collected in the creases after the 2nd OCI given the nearly identical usage parameters.

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Congrats, you've joined an elite club here on BITOG of those who look to see if the filter has captured any debris at the bottom of the pleats. I wish more would do this, as it can reveal valuable insights to what is going on inside the engine.

The higher additized HDEO is loosening deposits and carrying them to the oil filter.
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Yes, the first and last two photos are HDEO, PCMO respectively. I named the files accordingly but I now realise the names aren't visible by default on all devices.