Moderator: volvite
smj999smj wrote:Usually that's just the sound of the coolant running through the heater core that people hear and it's not a problem. You could try purging the system to make sure there isn't any air in the system to see if it helps. With the engine cold, remove the cap and install a "spill-free funnel."
https://images-na.ssl-images-amazon.com ... SX300_.jpg
Pinch off the return line to the reservoir and fill the funnel until the coolant reaches about 1/3 of the way up. Jack up the front of the vehicle as much as safely possible (or park uphill) and start the engine. Turn the heater(s) on to maximum heat and fix the throttle so the engine will run around 2000-3000 RPM. If you have a VG engine, crack open the air bleeder and purge any air out of it than close it. After about 10-15 minutes, make sure there are no air bubbles coming up through the coolant into the funnel and you have good heat coming out of the vents. If good, shut off the engine, remove the funnel and install the radiator cap. Lower the vehicle.