V9x/ d40 stx550 engine oil
- Thread starter Maccastx550
- Start date
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I don't think we need to worry about engine tune for the oil.
The oil labels do have important meanings, I'll try to keep this brief. Oils are described with two parts: the cold temperature performance and the high temperature/load performance, separated by a W.
The first number is the low temperature figure, and is a rating given to the oil based on how it behaves at low temperatures. The lower the number, the more the oil flows in cooler weather, which is important for ensuring that the oil flows into bearing gaps even when the engine is starting while it's cold.
The second number is how well the oil maintains its viscosity at high temperatures/loads. a 5W30 oil is good for cold/cool weather starting, but becomes much thinner (flows faster, perhaps too fast) under high operating temperatures than say 5W40.
Specifically: the first number represents the oil's viscosity at -30 degrees celcius. The second number represents the oil's viscosity at 100 degrees celcius.
You could use 5W40 oil easily, anywhere in Australia, and never have to worry.
But you won't need to make any adjustments to the engine tune.
As for the DPF - your oil must be "very low ash" - I think the oil standard was JASO-FD or better (so JASO-FC isn't good enough). This is because oil passes through the PCV as vapour and is often caught as ash in the DPF, blocking it up. Low ash oil doesn't cause this problem.
Does that help?
The oil labels do have important meanings, I'll try to keep this brief. Oils are described with two parts: the cold temperature performance and the high temperature/load performance, separated by a W.
The first number is the low temperature figure, and is a rating given to the oil based on how it behaves at low temperatures. The lower the number, the more the oil flows in cooler weather, which is important for ensuring that the oil flows into bearing gaps even when the engine is starting while it's cold.
The second number is how well the oil maintains its viscosity at high temperatures/loads. a 5W30 oil is good for cold/cool weather starting, but becomes much thinner (flows faster, perhaps too fast) under high operating temperatures than say 5W40.
Specifically: the first number represents the oil's viscosity at -30 degrees celcius. The second number represents the oil's viscosity at 100 degrees celcius.
You could use 5W40 oil easily, anywhere in Australia, and never have to worry.
But you won't need to make any adjustments to the engine tune.
As for the DPF - your oil must be "very low ash" - I think the oil standard was JASO-FD or better (so JASO-FC isn't good enough). This is because oil passes through the PCV as vapour and is often caught as ash in the DPF, blocking it up. Low ash oil doesn't cause this problem.
Does that help?
