Honda FourTrax Rancher TRX420FA5 2019 Owner's Manual page 153

Radiator Core
Refer to Safety Precautions on page 107.
Check the air passages for clogging or damage. Remove insects,
mud, or any obstruction with low water pressure. Have the radiator
checked by your dealer if the air flow is restricted over more than
20% of the radiator surface.
Clean the radiator core after riding the ATV in mud.
To clean the radiator core and radiator grill cover:
1. Unhook the reserve tank tube (1).
2. Remove the reserve tank (2) from the left radiator grill cover (3)
by removing the bolt (4) and clip (5).
3. Remove the clips (6).
4. Unhook the tab A (7) and tab B (8) on both of the left and right
side.
5. Unhook the left side of the center radiator grill cover hook (9) and
slide the left radiator grill cover.
6. Remove the left radiator grill cover.
NOTICE
Do not apply pressured water directly to the radiator core.
The pressured water can damage the radiator core.
Coolant
Servicing Your Honda
(cont'd)
143