When replacing an engine water pump, what should be done after draining the coolant?

After draining the coolant, the next step in replacing an engine water pump is to detach the pump. This is crucial because the removal of the old pump is a necessary step before any new installation can take place. When detaching the pump, it's important to also check for any debris or old gasket material that may need to be cleaned off to ensure a proper seal on the new pump.

While other options might seem relevant in the context of water pump replacement, they do not follow the necessary sequence. Installing the new pump cannot happen until the old one has been removed. Replacing all hoses may not be required unless they are found to be worn during inspection, and checking the thermostat, although significant, is also not the immediate next step in the replacement process. Each step must be approached in order to maintain the integrity of the engine cooling system and ensure a successful water pump replacement.