Thursday, Aug 11, 2011 at 08:54
Oils ain't oils ... or something like that. These top 3 are all API rating GL4.
It's a pitty I couldn't put a table in here and it automatically removes multiple spaces.
Product,Grade,Visc@40C,Visc@100C,ViscIndex,PourPoint
Mobil Mobilfluid 424,80W,55,9.3,145, -42C
Castrol VMX80,75W/80W,59.2,10.5,160,-32C
Caltex Textran THD,?,57.5,9.5,148,-39C
for comparison an auto trans oil ...
Mobil 1 Synthetic ATF,?,34,7.6,199,-54C
and a standard gear oil ...
Mobil XHP 75W-90,75W-90,100,15.5,165, -45C
By the way Mobilfluid 424 and
Mobil Agri Fluid 424 have exactly the same specs.
So what does this all mean? The Grade is an easy way of showing the oil's characteristics but each rating covers a certain range so is not particularly useful if you want to know the specifics. Vicosity at 40 degrees and 100 degrees are self explanatory and the Viscosity Index is basically a rating of how much the viscosity of the oil changes between 37.8C and 98.9C with a higher value being more stable. The Pour Point is the lowest temperature the oil will pour.
I suppose Mobilefluid 424 is slightly better of the ones discussed if we want to try a non-standard oil because of its lower viscosity.
Stay tuned for some oil changing shannanigans.
AnswerID:
462311