STEVE - I put 1400 HOBBS hour meter hours on a K241 Kohler doing everything from mowing, running the snow blower, plowing gardens and at several plow days, pulling My lawn aerator which pulls every bit as hard as My plow, pulling My lawn vac over My two-acre yard that can weigh up to 2000 pounds while running the mower deck And running it 12 hours straight without shutting it off. I didn't care about the paint on the engine...I'm worried about the engine lasting, not getting too hot, oil breaking down.
The only way to really know what makes a difference on engine cooling is to put gauges on Your engine...three are needed, Oil temp, cyl. head temp, and EGT.
The K321 I have in that tractor now is "cooling challanged", small dia. flywheel & blower housing. I need the gauges on it but I can't find room enough to mount them all. I've done a LOT of research about what temp. range all these things should run at. Even discussed with a couple Engineers who post here from time-to-time about what temps things should be. Maybe this next summer I'll make a panel and mount those gauges. It'll get a tach too. I've looked at many types of digital & analog gauges. They all seem to take up more room that I have available.