This is just my thoughts but it sounds right to me. Cat added the bigger heat exchanger right before the sleds went into production to prevent a potential problem. That is part of the reason that the first reported dry weight is off. I figure that all the sleds that they tested last winter had the smaller heat exchanger in them and that is why they didnt find out about the air bubbles in the coolant untill now. Im guessing that they didnt have much test time on the bigger exchanger. They tried to fix a problem and ended up with a different problem. What are the odds of that!! Im not to worried cat will take care of it.