Remember my other post when I said to leave a shop that says they use “universal” fluids in Hondas? This is the shop. LEAVE. The mechanic does not know what he is talking about.
Castrol is the cheapest name-brand oil sold at my local Wal-Mart. This is why the guy recommends it. Heck, I recommend it and use it in my Toyota. Never in a Honda.
BTW, Honda says in their book you can use another type of MANUAL transmission fluid as a temporary emergency replacement, but to drain and fill it with Honda fluid ASAP. Do not do this with an automatic.
What makes me Mr. Expert? My wife has this exact same car (2004 Civic) which runs and drives like new after 130k miles because I follow the “severe service” schedule in the owner’s manual.