Throwing this idea out to the masses: Why not run a different coolant? Bear with me, there is a story...
Back in 2004, I was looking for ideas to shave weight off of my (cough, cough) ski-doo rev 159. The cooler was huge, and perhaps overkill for the chassis. I cut the cooler to half it's original size, and started using Evans NPG+ coolant. Sled never ran hot, and I kept that machine for three seasons. It protects down to -40F, and doesn't boil until 375F, and unlike regular coolant, it doesn't expand nearly as much when heated. I've been fortunate enough to not split my tank, but it is insulated, my exhaust is fully wrapped, and I'm using Cat's vented side panels (mine is a BC250 kit). One could hear the coolant boil from the turbo when stopped, and I topped up after every trip, as it would push coolant from the tank overflow periodically. I'm open to suggestions / comments, but my plan for the upcoming season is to switch both sleds over to Evans and run a lower pressure cap to get rid of some pressure, and prevent the boil from the turbocharger. I'm not affiliated with then or selling anything, but it might be worth a look - I know I'm going to try it...
