Can you mix SAE 30 and 10w30?
Moreover, can I use 10w30 instead of SAE 30?
SAE 30- Warmer temperatures, most common oil forsmall engines. SAE 10W-30- Varying temperature range, thisgrade of oil improves cold weather starting, but may increase oilconsumption. Synthetic SAE 5W-30- Best protection atall temperatures as well as improved starting with less oilconsumption.
Hereof, is it OK to mix different weights of motor oil?
Mixing different oils will not improve theperformance or efficiency of the engine in any way. Theadditives in synthetic oil may have limited or no effect atall when mixed with a regular engine oil. You can use1 litre of 5W30 mixed with 5W40 and it will not cause anysort of ill effects to the engine.
It is pefectly fine to use SAE 30 oil in place ofthe 10W30, as long as you never let the oil get belowdegrees 50C. (100 degree c measured), so when your car isrunning at normal temperature the oil flows properly. Whenthe oil cools down, to 25C or thereabout, it is a lot less'slippery'.