I have a 2012 RAV4. V6 74000 miles. Upon cold start, intermittently only, I get a mechanical interference noise .Almost sounds like the starter not disengaging. The dealership has replaced some cam guides in engine says there is an issue with these,also on another visit they said it as a bearing going bad on water pump and replaced it. Both were done at no cost to me. I am trying to get noise on video to no avail. Any thoughts?