Auto radiators must be removed and installed to have major leaks repaired, or to replace them with new units. Because of the way the radiator in the 2000 Jetta is positioned, replacement is a long process and should only be attempted by someone that is knowledgeable about vehicle repair.
Park the Jetta on a flat, level surface and set the parking brake. Open the hood and secure it in place with the hood prop. Disconnect the negative battery cable. Allow the vehicle's engine to cool completely.
Place a bucket or deep drip pan under the radiator and open the lower radiator drain plug with a socket wrench. Allow the radiator to drain completely. Dispose of the coolant at a recycling center or auto garage that accepts recycled petroleum products.
Unplug the wiring harnesses connected to the headlights. Remove the screws holding the headlight assemblies in place with a Phillips screwdriver, then pull the headlights forward and remove them from the vehicle.
Remove the bolts securing the front bumper with a socket wrench. Remove the front bumper assembly from the Jetta.
Loosen the hose clamps on the upper and lower radiator hoses with a flat head screwdriver. Grip the hoses securely and disconnect them from the radiator. Unplug the thermal fan and cooling fan electrical connectors.
Remove the two bolts holding the upper part of the radiator in place. Lift the radiator and fan assembly out of the vehicle until the lower hoses and lines are accessible.
Disconnect the power-steering cooling lines. Remove the air guides with a socket wrench. Unplug the fan assembly and pull it free of the radiator. Finish removing the radiator from the vehicle.
Connect the fan assembly to the new radiator and reassemble the Jetta in the exact reverse order it was taken apart.
Place the bucket under the radiator and pour a few gallons of water through it to clean out any dirt and dust. Install the radiator's lower drain plug. Fill the radiator with a mixture of half water and half coolant.
Turn on the Jetta and let it run for a couple of minutes. Add water and coolant to the radiator until it is full. Put the radiator cap back on the radiator.
