trigger
Old Ironsides
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Damn, good stuff joey! Learned more about oil, reading that post, than I ever knew before. Sorry to hear that Mobil 1 isn't what I thought it was, that's what I run in my Sierra and my John Deere. Run Royal Purple in a little Cobalt that has 275k, she still purrs. Based on what I read, SAE 30 should stay 30 until it gets old and starts breaking down right?Multi viscosity weight oils are measured by a viscometer. The rate of flow is measured at 40°C and 100°C. Based on the flow at 40°, it's given its "winter" grade. Based on its flow at 100° it's given its high temp grade.
In an engine, typically the engine oil will reach 100°C by design. That's the way it's designed so that any moisture that gets in the oil will steam off thru the crank case vent. For differentials, it takes them a little longer to warm up obviously due to not having combustion.
This is an interesting topic though as I've not read diff case temps and I may consider that just for my own curiosity.
If you would like to read more, this would be an interesting read.
Oil education