In Reply to: Re: Anyone using CASTROL Syntec 5w50 oil? (more) posted by Henry on April 30, 2000 at 20:20:37:
: : I don't much care for the "30" in the new BMW oil but I'm also not too wild about the "45" spread of the CASTROL 5W50 either. I guess the "45" spread will be okay because the new M5 uses only CASTROL (BMW labeled) 10W60 which has a "50" spread!
: : Any comments bood or bad about the CASTROL 5W50?
: : Bob ///M3
: The M5 has the governor to limit rpm's top range when the engine is cold. I think as long as you keep the rpm range low before the car warms up, a wide spread of oil viscosity should pose no problems.
Huh?? The only potential negative effect of a wide viscosity range is that, over time, there will be a tendency to degrade about 5 points off the top end...So that after, perhaps, 10K miles, an oil analysis at the lab may show a 'useful' viscosity of 5W-45 instead of 5W-50. Obviously, this has nothing to do with the dynamic redline the M5 uses due to warm up conditions.