snapping noise / engine compartment

[lking78]

2001 cobra -- have heard a sharp snapping noise infrequently -- heard it today as we put coolant in the car after the oil cooler re-build -- i have heard it just
after the car had been turned off -- it would happen 3 or 4 times as the car cooler off -- sounds similar to an electrical short snap to ground -- not regular at all -- when we heard it today while the car was running, my friend thought it was coming from the IRMC --

appreciate any thoughts -- many thanks

 

[RAU03MACH]

I would need a video of this happening
only thing that i could think right now is
when metal any metal changes temps cold to hot you will that something broke lose sound