1999 Honda Accord Radiator-upper hose

Yes, must drain and bleed.

Remove the actual hose is easy. Should just have two clamps to remove then pry off hose at each end. Information on replacing your entire radiator can be found at link below. You can use this as a reference for replacing your upper hose.

https://www.2carpros.com/how_to/how_to_replace_radiator.htm

To drain cooling system, remove the drain valve on radiator as shown in the link above.

To bleed the system, perform following steps.

Open the bleed valve on the thermostat housing 1/2 a turn.
Set the heater to the "full hot" position.
Fill the cooling system with a 50/50 mixture of a suitable coolant and water. You need a clear hose that will fit the bleed valve and a container to keep some of the fluid that will drain out during the process. You must have the engine running and in normal operating temp. Let the coolant drain until there are no bubbles coming out from the hose. Retighten the bleed valve and add more coolant as necessary. While doing this, also squeeze the upper and lower radiator hoses to help force out any trapped air pockets. Close the bleed valve once a steady stream of coolant is visible.
When mixing a 50/50 solution of coolant and water, using distilled water instead of regular tap water may help prevent the cooling system from internal deposit build-up.
With the radiator cap partially installed, start the engine, and allow the engine to run until the cooling fan runs two times. Turn the engine off and top up the cooling system and overflow reservoir as necessary.
Close the radiator cap, restart the engine and check for leaks.

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