JLG G5-18A Service Manual - Manual (Page 46)

Cab and Covers
4.10 G5-18A/2505
14.Start the engine and check the operation of all controls.
Check for hydraulic fluid leaks. Check the hydraulic
fluid level in the tank and add fluid as required.
15.Wait for the engine to cool and check the coolant
level. Add coolant to the overflow bottle as required
to bring the coolant to the proper level.
16. Close and secure the engine covers.
NOTICE
When the engine is initially started, run it briefly at low
idle and check the machine for any visual sign of fluid
leakage. STOP the engine immediately if any leakage
is noted, and make any necessary repairs before
continuing.