350 yamaha bruin 4x4 broke oil cooler while riding now pecking loudly

I have a 2005 yamaha bruin 350 4x4.  I was riding one day and something kicked up into the oil cooler breaking the connector right at the seam.  I did not notice anything wrong till i heard a change in the motor tone.....I slowed to a stop and the motor shut off on its own...(bad feeling to have to be where i was)....I took a look around and seen where the oil had been draining on the suspension then the ground. Needless to say when I checked the oil the stick was dry.  After fixing the oil cooler when it is cranking over the oil light comes on but only when cranking....when it sarts there is no smoke and it has perfect compression but there is a loud pecking from i believe the top end of the motor and the oil light also come on. An Any info will be much appreciated.......Jon