We just had the timing belt and water pump replaced in our 2000 Honda Accord 2Dr Coupe. My wife said on the way the car started making a boiling sound. It's not running hot. Any ideas?

 

Air is commonly trapped inside the cooling system after a major service like that, the easiest way is to let the engine completely cool back down, perhaps even overnight just to be safe and pop the radiator cap off and top off the fluid, it is usually low. On some cars there is a bleeder screw on the thermostat housing that is used to also let out that air and I'm pretty sure you do that when the engine is fully warmed up and at an idle. Way easier and safer to let it cool down and top it off, then if still doing it may need to try to bleed the system. The noise you are hearding is the trapped air bubbles going through the heater core inside the dash board.

 

4-cylinder engine?
Use the bleeder valve when the engine's cool. Open the radiator cap then open the bleeder until the air comes out & the stream is all-liquid. Top up the radiator & put the cap back on.