Up to 80% of engine wear occurs during first startup (cold engine regardless of temperature). The time it takes for the oil to reach the vital engine's components and parts. That being said, for the best and fastest protection during startup is using an oil that has a 0w viscosity rating. Example, if your engine requires (designed to use) 5w-30 oil (w stands for winter) you could/should substitute that oil with 0w-30. This will ONLY allow the oil to flow faster during startup, regardless of what climate you live in. Now if you want the best engine oil protection you should find out (from the Stealer) if you can use full synthetic oil. If it is OK, I highly recommend using ANY full synthetic that is in the recommended ratings. Full synthetic oils have a much better flow rate. Do not use a higher rated viscosity than recommended, thinking it is better for higher temperatures. The higher rating difference is the actual size of the molecules which are larger in size and will not provide lubrication until they break down. (The molecule can not enter the bearing until it is broken down.) Example, substituting 5w-30 with 5/10w-40.
Being that the engine oil is shared with the trans (clutches) you absolutely need the consult with the stealer to make sure the use of synthetic oil is OK!!!!!