how much is it to fix heater hose underneath the manifold,

Hello, That is something specific to the modular Ford engine, so we will not have a quote on that specific repair. Also, based on findings once the manifold is removed, the water pump may be recommended for replacement as that is the connection that leaks for that coolant pipe. The good news about that is that the water pump is already accessible to remove when removing the intake manifold, so the additional cost should only be the part. That is if you have to change it.