I have found that I have more heat resistance than many non fan equipped water pumpers. They are puking out coolant and I'm still going strong. Dont even question the XRL's ability to cool properly. Unless like cleonard said, sand hill climbs/drags. They do just fine, even compared to coolant puking water heads! Uh-huh. And just how would you know if your 650L was overheating? Just because a water-cooled machine spits a little steam doesn't mean its running hotter than an air-cooled.