ALL cold starts rely on existing residual film. There is no "flow" happening for the first few revolutions as the engine lights. How long does it take for the oil pressure light to go out on your motor? If it's longer than instantaneous, the motor is relying on existing film everywhere...
And piston skirts, wrist pins, cam chains, and the like are never lubed by pumped oil anyway, so how would they know about "flow" ...
Use what makes you happy. It's your $ for the truck and for the oil. There's a pretty good probability that if the motor goes south (and following a bathtub failure curve, if it ran off the lot, it'll prolly get to 100,000), the first thing that will happen is that they'll drain the oil and drop the pan ... Likely they'll loose the oil. As long as it's not obviously too thick on inspection, they won't care. If it looks dirty, chunky, black, gritty, etc. - they will come at you from an oil angle...
If it were me and I had that much invested, I'd run the "thickest" oil I could find that met factory spec out to warranty. Then switch to 10W-30 or 15W-40 depending on what I had for bulk oil on the ranch at the time (I have both right now)... We all know that all oils are the same. One of the 5W-20 is on the thicker side of that equation. Just use it for now
And piston skirts, wrist pins, cam chains, and the like are never lubed by pumped oil anyway, so how would they know about "flow" ...
Use what makes you happy. It's your $ for the truck and for the oil. There's a pretty good probability that if the motor goes south (and following a bathtub failure curve, if it ran off the lot, it'll prolly get to 100,000), the first thing that will happen is that they'll drain the oil and drop the pan ... Likely they'll loose the oil. As long as it's not obviously too thick on inspection, they won't care. If it looks dirty, chunky, black, gritty, etc. - they will come at you from an oil angle...
If it were me and I had that much invested, I'd run the "thickest" oil I could find that met factory spec out to warranty. Then switch to 10W-30 or 15W-40 depending on what I had for bulk oil on the ranch at the time (I have both right now)... We all know that all oils are the same. One of the 5W-20 is on the thicker side of that equation. Just use it for now