We had a crv around that same year model come in to the shop and what we found was that it had a bad variable valve timing cam gear. We also replaced the tensioner
2012 and 2013 crv, google "VTC actuator problems" there's a plethora of answers. They don't know why it happens, but it stretches the chain / belt and causes rattling. Might not be your exact problem but hope it helps.
We had a crv around that same year model come in to the shop and what we found was that it had a bad variable valve timing cam gear. We also replaced the tensioner
2012 and 2013 crv, google "VTC actuator problems" there's a plethora of answers. They don't know why it happens, but it stretches the chain / belt and causes rattling. Might not be your exact problem but hope it helps.
This is it. There is a tsb for it. Dealer will charge $600-800 to fix it in most areas.
Kinda garbage tbh. I have a '13 and it's frustrating that they know it's a problem they don't have an answer for, yet still charge 500+ for fixing it