Update MF 5610 radiator cap leak

This is a diagnostic follow-up on a coolant reservoir cap that's been leaking on a 2013 MF 5610, not a repair or fix. The owner closely examines the cap and reservoir threads, demonstrates cross-threading with calipers, and compares the cap design against a John Deere 6415 for contrast, concluding it's likely a design flaw he plans to report to the dealer. Useful for 5610 owners troubleshooting the same leak, not general buyers.

Posted by an owner working through a mechanical problem on his own tractor in real time, with no resolution confirmed yet.