I am positive my Service Advisor said 5000km, and am convinced if anyone at a showroom says 2500km interval, they don’t know what they’re talking about or they just want more money. This new engine isn’t as maintenance intensive as the older ones. Also, I’m attaching our own owners manual (p. 507) recommendation that applies to Pakistan. For dusty environments, they recommend a 5000km OCI for the 1GD and 2GD. “Others” includes the 1KD-FTV and 5L-E Toyota engines.
If you see p. 500, it tells you the “normal” change interval is 10,000km/6,000miles or 12 months, but at least in Karachi it’s too dusty for that.