When I go up long hills like towards Nuwara Eliya, temp needle slowly climbs near red. Fan belt and coolant all ok. Radiator cleaned last year. Do I need an oil cooler or just better fan?
Climbing hills like Nuwara Eliya will heat up older diesels fast. If fan belt, coolant, and radiator are fine, check if you're still using the stock engine fan sometimes it's not enough under load. Upgrading to a better mechanical fan or adding an electric pusher fan can help. Oil cooler helps too, but try better airflow first before adding more systems. Also worth checking thermostat and water pump if not replaced recently.