I have a 97 Civic and when I accelerate I hear a sound like water is rushing through a pipe. It sounds like it's coming from the driver's side. I'm assuming it's the water pump, but why would it make this noise, and is it necessarily bad?

 

I think you may be hearing water moving through the heater core. Check whether the coolant is low and then also bleed the cooling system of possible trapped air.

 

The coolant isn't low, and has been okay for about 6 months after I flushed it. I'll try bleeding it if that could be it. When I flushed it I drained it all from the radiator, replaced the thermostat (and consequently all hoses going into the housing), but I did not flush the heater side, so that should be the only residual coolant.

 

Bleeding when engine is cold:

Park on incline with engine higher than the rear.

Set the dash lever to MAX heat.

Remove the radiator cap and top off radiator and reservoir with coolant.

Reinstall radiator cap loosely.

Start engine and let it idle until the radiator fan comes on twice. This could take 20-30 minutes.

Top off radiator and reservoir again with coolant and then tightly reinstall the radiator cap.