the FSS is fine as long as you are using a decent oil like M1 0W40 or similar. The most important part to make sure is running temperature, make sure the engine gets hot and toasty before ramping on it.

The sump capacities of these engines are nearly twice the usual similar sized engine. Hence it can take a while to beat down the oil - a really long while with a nice oil.

I have noticed that with synthetics the oil gets dark but the engine casings are very clean. I think its just the nature of it.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)