Re: Oil pressure question

Posted by Fish'n Jim On 2021/11/7 10:01:23

Lots of confusion and hearsay on oils, mostly due to marketing info.(opinion)
The rotella is formulated for diesel engines which have a higher soot load/cylinder pressure. There's no problem using it, so long as your in the visco range. Some are using the 15-40, which is not what you probably should. Mostly higher visco affects the early pickup of the oil pump when cold. Pump needs some viscosity to function but if oils stiff then it won't flow well to the inlet when it's needed most, at starting, increasing wear.
10-30 and 30 will be the same at the operating temperature. Otherwise, it won't say 30 in the second number.
They just add viscosity modifiers and test the oil at two temperatures to get the numbers. It's compared to the straight base oil numbers.(SAE/ASTM methods) There's not that much real difference as the numbers indicate. eg; 30 is not 3 x 10 here. (I have the curves.) It just the accepted method of yore.(tradition)
I personally don't like using the modern diesel additives, in an older engine that's not been rebuilt and possible sludged a tad.
Some sludge dislodges and plugs your passages and bad things will happen. You have to change frequently at first til no more crud. Oil service used to include annual pan cleanings.
You don't say what year or if it has partial or full filter or not, or condition/mileage, making ticking noise or not, etc. Covering the bases.