Not buying into this ... on a cold start in the winter the engine oil needs to warm to some extent to allow for proper lubrication. Not doing so puts additional stress on the engine. A warm weather start ... not so important
All this speculation about cold engine oil is absolutely correct. Todays engines are tighter tolerance and some have roller bearing valve trains that require more cold start oiling. Engineers have determined 40% of normal engine wear is the result of dry starts, hence their requirements of thinner and thinner oil.
Indy car engines are not started without pre-heating the oil as well as the coolant and even after startup they are carefully taken to operating temperature. They use 0-5wt. oils and there is talk of using 0-0 wt oil.
I have a small motorhome with a Ford v-10 that the factory says use 5-20 oil and the previous owner had 10-30 Pennzoil put in it. Hydraulic lifter tick on start up for 10-15 seconds. I had the oil changed to Valvoline 5-20 and by the 8th or 10th start up the tick was gone and pressures were normal. I just gotta get the 10-40, 20-50 mentality flushed outta my brain. Lawdy, lawdy, help me with the straight 50wt in my Cessna!!!! Thick oil equals wear.