Should I start using synthetic oil in a 2007 C-RV with 240K miles on it ?

What is your question?

2007 C-RV, 244,000 miles, Pennzoil 5-W20 only since purchased new, no additives other than Techron in gas once every year

What makes this problem better or worse?

N/A

How long has your 2007 Honda CR-V had this problem?

N/A