And, of course the answer here is air flow, not coolant flow. The whole system depends on the amount of air flow the radiator receives, and how to manage the air flow through the radiator. That’s why a shroud and a puller fan is vital to the coolant being cooled. A proper shroud and clutch fan is the best setup to getting as much air flow as possible. And, a lot of that had to do with the radiator. There needs to be a balance between how much fluid volume the radiator can handle, and how much air flow can pass through the system. If you add cores to the radiator, or larger cores, that doesn’t mean it will cool the fluid any faster. A puller fan like the stock units create a vacuum, pulling air through the radiator, and a shroud helps channel that air through the radiator. Once a vacuum has been established, the air in front of the radiator is pulled towards the vacuum, sort of straightening the air as it passes through the radiator. More obstruction creates less air flow. I think of it like a funnel, you can either pour liquid around the edge of the funnel, and swirl the funnel, and liquid will go right down the hole. Or, you can dump it in all at once, plug up the hole, and wait for the liquid to go down. Channeling the air through the radiator by pulling it is the most efficient method to maximize air flow. An electric pusher fan does not do this, and will push some air through the radiator, but the radiator will act like a block, and the fan can only force so much air through. More cores, the harder the fan has to push for less air flow. And, that is only where the fan is, the other part of the radiator has to rely on the ramming effect of driving to create wind, and still forcing air through the radiator. Air takes the path of least resistance, so where will the air go? That’s why temps go up when the car is stopped, no air flow.
But, I digress here, I know nothing, and YouTube videos are always right and have been for decades. So, what is the purpose of a 160 thermostat then, I ask?