Shell Helix Ultra 5W40 (MB229.5)
Oil Life : 14,184 km
8 months oil life thus far since Sept 2023.
ODO :380,740 km in
Car model: Toyota Avanza 1.3L
Note:
Top up at 12,000 km about 0.8L of mineral Shell Helix 15W40 (Yellow packing, SN) -due to timing cover oil seal leaks.
Samples were taken hot within 5 minutes of engine shut down after a 20-25 minutes drive.
48 hours blotters:
a)With back light
b)With NO back light
The Centre Zone (of about 8 mm diameter) is clear, transparent and not grayed, indicating absence of usually higher level of high density/heavy metal wear particles typically found in a 14K km blotters.
Question: Where has the typical heavy metal wear particles gone or why seems to disappear?
The aureole zone/perimeter ring (of about 10 mm diameter size) is absent and not darkened indicating absence of agglomeration of combustion by-products in the blotter sample.
It represents the usual capability of detergents in a used oil to disperse contaminants within the used oil sample.
At 14,184 km usage, the Diffusion Zone here is not grayed or darkened/opaque indicating an unusually low level of light/low density combustion by-products/contaminants despite its 'high' mileage of 14,184 km.
Please note the outer annulus of the Diffusion Zone (that stays within darkened zig-zag edge) remains clear and light coloured and not graying/darkish - which appears to be ready to absorb additional amounts of oil contaminants in this 14k km used oil sample.
Darkened zig-zag outer edge that is clearly seen here indicating presence of oil oxidation phenomenon and/or presence of moisture.
Translucent halo is obviously present on the outermost zone (encircling the zig-zag edge) indicating presence of fuel dilution phenomenon in this 14,184 km blotter sample.
Note: Daily driving pattern is 11km over 20-25 minutes one way in KV.
As usual, there is no indication of coolant contamination of used oil.
Despite its rather lengthy usage of 14,184 km thus far, imho this used oil (with some 0.8L top up in between) is still serviceable.
Hence I've no intention to get this used oil replaced at 15,000 km interval - strictly basing on the current blotter spot 'performance'.
We'll see how long further can this oil change interval be extended well beyond 15K km without harming the engine.
This post has been edited by zeng: Jun 22 2024, 11:22 AM