Originally Posted By: CATERHAM
Originally Posted By: lockguy
Im wondering why people tend to use a "thicker" or higher viscosity oil in hotter climate. The thermostat keeps the engine about the same operating temp whether in hotter or colder climates right?
To me, it is more of a decision of how much protection do you need vs effeciency savings...any thoughts?
It's not about using a thicker or higher viscosity oil in the hot summer months (or in a hotter climate generally) and therefore more protection but rather attempting to maintain a certain minimum operational viscosity.
Put simply, heavier oil grades may be necessary to compensate for the very much higher oil temp's that can occur with higher ambient temp's.
In vehicles with exposed sump's and without coolant/oil heat exchangers, the difference in maximum oils temp's can easily be as much as 50C or more between the frigid depths of winter and the mid-day heat under a blazing sun raising asphalt temp's to as much as 65C (and the above boundary air layer) of summer or more.
Every grade from 5W-20 to 20W-50 (0W oils weren't generally available yet) are specified for my older Porsche based largely on ambient temp's to try and achieve that same desired operational viscosity. Today it is just one grade that's recommended, 0W-40, for all ambient temp's and all Porsche engines (like many manufacturers) have coolant/oil heat exchangers. This greatly stabilizes maximum oil temp's so that the affect of ambient temp's is mitigated to a large degree.
+1
Originally Posted By: lockguy
Im wondering why people tend to use a "thicker" or higher viscosity oil in hotter climate. The thermostat keeps the engine about the same operating temp whether in hotter or colder climates right?
To me, it is more of a decision of how much protection do you need vs effeciency savings...any thoughts?
It's not about using a thicker or higher viscosity oil in the hot summer months (or in a hotter climate generally) and therefore more protection but rather attempting to maintain a certain minimum operational viscosity.
Put simply, heavier oil grades may be necessary to compensate for the very much higher oil temp's that can occur with higher ambient temp's.
In vehicles with exposed sump's and without coolant/oil heat exchangers, the difference in maximum oils temp's can easily be as much as 50C or more between the frigid depths of winter and the mid-day heat under a blazing sun raising asphalt temp's to as much as 65C (and the above boundary air layer) of summer or more.
Every grade from 5W-20 to 20W-50 (0W oils weren't generally available yet) are specified for my older Porsche based largely on ambient temp's to try and achieve that same desired operational viscosity. Today it is just one grade that's recommended, 0W-40, for all ambient temp's and all Porsche engines (like many manufacturers) have coolant/oil heat exchangers. This greatly stabilizes maximum oil temp's so that the affect of ambient temp's is mitigated to a large degree.
+1
