My '94 Accord's Owner Manual recommends SAE 5W-30 engine oil with API
Service SG or SH. However, the latest Castrol 5W-30 GTX oil that I have
been using comes only with API Service SN, SM, SL, SJ codes. I suspect
these codes might have superceded the older SG and SH codes, but I am
not sure. Anybody knows more about this?