Never block any cooling system or parts of it or anything like that, it's just asking for trouble. All it takes is you block it a little too much and it works fine until you get in the middle of some bumper-to-bumper 80-90mph I-95 style traffic when it decides to overheat and you can't pull over and then you end up with severe damage to the engine or transmission...
This kind of stuff doesn't make much sense for gassers, most of your engine is running at the temperature your thermostat dictates anyhow, so if you have a 160 degree thermostat installed then the engine runs at that temp regardless how cold it is outside and how much air is rushing through the cooling fins. Water won't circulate until the engine temp reaches 160 then the thermostat opens for a bit and once it has cooled down it closes back up.
It is even unlikely the engine will reach operating temperature faster on a very cold day, diesels benefit from it because their burn temps are cooler so they heat up quicker with a blocker, but a gasser if it takes too long is nothing you can do... If it's an older steel engine that takes 20 solid minutes of driving to heat up then that's how it is, but an aluminum engine can get to optemp within 4-5 minutes of driving, maybe a little longer, but blocking the radiator will not make it heat up faster, almost guaranteed you'd about have to wrap the whole engine in some type of thermal blankets
So, the way to run it hotter is get a higher temp thermostat for 5-10 bucks and experiment that way, I'd go 1-2 ranges higher than where you are, if you're already at your highest then this is gtg.
Because believe you me, even a hotter thermostat can start the repairs, but this is by far the more proper method.
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