Number_Cruncher
Active Member
I suspect that it will be difficult to find evidence of a modern engine in normal use which has had an inadequate life purely because of the use of 30 weight oil compared with 40 weight oil.
I don't dispute that 40 weight oil gives larger part clearances, but, it's a question of adequacy. My contention is that 30 weight oil is adequate for normal use, and, I think the evidence of thousands, if not millions, of motor cars tends to side with that.
With increasing life expectancy of cars, and the financial squeeze caused by the credit crunch, the reasonable life of a car is probably being re-defined upwards. Perhaps when people routinely run cars to 200K**, lubrication based engine failures will become more important again, but at the moment, I don't see it being too important.
** I'm sure there are many on here who have long since passed 200K, but, for "normal" use, most cars have been crushed by this point.
I don't dispute that 40 weight oil gives larger part clearances, but, it's a question of adequacy. My contention is that 30 weight oil is adequate for normal use, and, I think the evidence of thousands, if not millions, of motor cars tends to side with that.
With increasing life expectancy of cars, and the financial squeeze caused by the credit crunch, the reasonable life of a car is probably being re-defined upwards. Perhaps when people routinely run cars to 200K**, lubrication based engine failures will become more important again, but at the moment, I don't see it being too important.
** I'm sure there are many on here who have long since passed 200K, but, for "normal" use, most cars have been crushed by this point.