If the coolant is full and the fan is working, suspect the thermostat needs replaced. I would also flush the cooling system when replacing the thermostat.
Here are two links related to replacing the thermostat and flushing the cooling system:
Here are the directions specific to your vehicle. The attached pic correlates with the directions.
2003 Honda Truck CR-V 4WD L4-2.4L
Vehicle Engine, Cooling and Exhaust Cooling System Thermostat Service and Repair Procedures
1. Drain the engine coolant.
2. Remove the splash shield (see step 22).
3. Remove the lower hose, then remove the thermostat.
4. Install the thermostat with a new O-ring, then install the lower hose.
5. Install the splash shield (see step 23).
6. Refill the radiator with engine coolant, and bleed air from cooling system with the heater valve open.
Let me know if you are able to find any vacuum leaks.
Monday, July 6th, 2020 AT 9:41 PM