Hey guys,

I've got a 2009 Toyota Prius with 67,800 miles on (as of March 2021) (I am the first and only owner).   I've noticed some time now that there is a clacking sound from the gas engine when the car starts and continues while idling.  I generally don't let it idle for long, however.

I've kept up with regular maintenance, use standard (non-synthetic oil), and do regular oil changes about every 5,000 miles.

I've read that valve adjustments on these suckers are VERY expensive, and most of what I've seen says that I should leave the engine alone unless there is SERIOUS clacking or engine shake (which is rare for 2nd Gen Priuses).

Am I doing any long-term damage to the engine by leaving it alone?   I don't want to use a heavier oil than specified, because Scotty is clear that it might actually do more harm (lubrication-wise).    Any thoughts about next steps?

Thanks much!!