QUOTE(Trony @ Jun 7 2019, 02:14 PM)
Just to share mine.
Car Type/Utilization/Speed/RPMType : Honda City iDSI Y2003
Utilz: 5.2km/week
Speed: <90km/h
RPMĀ : <3000r/m
Last ODDate: 04/02/2015
Odo : 50,709km
BlotterDate: 04/06/2019
Odo : 57,506km
EO Type/AgeType: Honda Semi Syn 5W30 4L
Age : 4y4m & 6,797km
Thanks for posting , Trony.
The centre zone is quite dark, indicating rather substantial levels of combustion byproducts , acidification etc.
Good news is there is absence of dark solid perimeter ring in centre zone , indicating the oil's dispersancy/detergency capability has not badly broken down yet, hence no irrepairable severe engine damage has occurred despite 4.5 yo oil in use.
Would I recommend 9000 km OCI and beyond ? Probably not and I personally may be comfortable at up to 7500-8000 km.
In a way, this 4.5 year old engine oil is not causing excessive engine wear rates , yet.
The darker centre zone is also caused by oil oxidation from unusually low usage AND long oil age, but it is still holding up fine ..... may be not for too long from now.
Outermost zone obviously indicate quite bad fuel dilution problem whereby its Kinematic Viscosity at 100*C (KV100C) may have dropped to 7.5 -8.5 cSt from virgin KV100C of around 10.5 cSt.
In a way this unusally low viscosity (caused by fuel dilution) is bad but I believe it's not causing bad metal wear due to your low usage and cold engine oil in operation most of the time.
The intermidiate zone is not darkened yet, indicating it has additional capacity to absorb more contaminants. However ,dark coloured solid centre perameter ring (representing failure in detergency/dispersancy oil capability) is something you want to avoid and look out for.
This post has been edited by zeng: Jun 9 2019, 09:53 PM