pulsating pump

[wyo]

What causes water pump to pulsate? I don't remember it doing that last year.
Any suggestion's, answers or comments?

[lcv800]

Pretty sure they all do.
Rusty

[hddecker]

Check the fittings to make sure they are tight and verify the heater bypass valves are in the right position. If there is any air being introduced on the intake side it will change the sound of the pump, as does a valve in the wrong position.