Any other radiating method we don't know about?

[Treetop64]

I mean this respectfully, but if you're chronically overheating the LaGG-3 like that then you are fundamentally doing something wrong. The LaGG is one of the most overheat resistant planes in the game if you do things right.

Generally speaking, to get the most performance out of any engine in the sim for the longest practical time, you want to set a high manifold pressure, combined with a moderately reduced RPM, and as high a mixture as practical for a given altitude. Also, you may want to open the radiator one or two steps. Moreover, you want to fly in a manner that keeps your speed as high as possible - the more air that is blasting into the radiator for liquid-cooled engines, and through the cylinder head fins for air cooled engines, the cooler your engine will run. Again, this is a general rule of thumb for managing engines during combat in the game.

Can't stress this enough, but I highly recommend turning off HUD messages, and get used to reading the gauges to monitor the engine. With v4.11 you can do that with confidence now that the gauges show what they should show. I've said it many times and I'll say it again: the triggering of the ENGINE OVERHEAT message is way too conservative. I've long flown without HUD messages and have paid close attention to the gauges, and have gotten good performance out of the engines on warm and cold maps. Once I turned on HUD messages however, I found that the ENGINE OVERHEAT message came on far sooner than I would have otherwise started worrying about the condition of the engine. I just turned it off again and haven't used it since. If I used the ENGINE OVERHEAT message as a guide to start trimming back on engine settings, I would never get any decent performance out of the machine.

Learn to use the gauges, throttle, RPMs, manifold pressure, and radiator; not be a slave to the OVERHEAT message; practice consistently, and I promise you will get more performance out of your plane.