We have two 2008 Honda Accords, one for each college student daughter. Both have the 2.4L 4 cylinder engine and are in the vicinity of 150K miles. Both cars, when started cold, have a nasty sounding rattle for about a half second. It does not happen when the engines are warm. A local independent Honda-specific repair shop says it is the VTC actuator, and that it is a common issue with these engines. The repair entails a complete valve adjustment and runs about $600. The local Honda dealer agrees, but the service advisor told me that he has never seen this condition actually lead to a catastrophic failure. So, considering these cars are intended mainly to get our daughters through their college years, is this a high priority repair?
Yes, it is.
Why would you put off any needed repair? In the grand scheme of things $600 is a pretty cheap repair these days. If you can hear a rattle, there is damage being done. Ignore the service advisor, he is not a mechanic.