Though I've used Mobil 1 fully syn oil in a LOT of my vehicles i.e Corvettes, MB's, Volvo and others, WHY exactly do I have to use fully SYNTHETIC oil in my '03 X5 3.0i manual shift? I know it's factory recommended, but seems to me that an engine with 80K miles would require maybe a thicker dyno oil rather than syn oil(though mine has ZERO oil leaks anywhere).
I mean it's no problem to use it b/c I change my own oil, just curious to know if I could use a high grade dyno oil i.e. Castrol, Penzoil etc?
09-01-2010, 06:52 AM
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