This is my first post, please go easy on me, if this has been answered somewhere else. But, I changed the engine coolant today. Drained radiator and coolant overflow tank. And refilled both. Only took around 1.25 gallons to refill. So, it might be a little low. Went on a drive, now the normal noise when you shut the car off (that sounds like a pump) is different. It sounds normal at first, then changes pitch, and then back to normal. Almost like it's sucking air or something. It only started doing this after changing the coolant. So, my first thought is there must be air in the system from the coolant change. 2005 with 203k miles. I changed the inverter water pump around 150k. I have not checked any codes. No warning lights on. Any tips? Thanks in advance!!
Take the cap off the radiator (not the coolant overflow tank) and make sure the coolant is at the top of the rad. Doing it the way you did it should not have invoked an airlock. Its the way i recommend people do it. But maybe some air snuck in there. Take the car for a drive and then pull over and turn on the heat at max heat. Listen for any gurgling or rushing water sounds behind the dash. Should be quiet. if you hear anything you have some air in there. There's a bleed screw on the side of the rad on the drivers side. Its on the upper part of the rad facing rear. hard to see. It uses a hex key. I cant remember the size of the key right now. You start the car and open that hex bolt and let coolant drain out till no more sputtering. Go on youtube and search Prius Inspection Mode it will show you the chicken dance to put the car in inspection mode where the engine runs endlessly.
Thanks Ed. I believe I was able to get the air out today. The pump sounds normal now when shutting the car off.
