Periodic maintenance of the cooling system comes down to checking and repairing leaks, checking and restoring the fluid level, fluid condition, cleaning the radiator cap, radiator intercostal spaces, and checking the condition of the hoses. Checks are carried out on a cold engine at least 1 day before the trip, or at least 3 hours after the trip. To unscrew the radiator cap, turn the cap counterclockwise until it stops, wait for the gases to escape (a hiss will be heard), press on the cork and turn, remove. Add fluid if the level does not reach the base of the radiator filler neck. Replace hoses that show signs of hardening, swelling, material softening, or cracks. For serious damage (leak in the radiator) contact a service station.