My Prius makes a noise (maybe a pump noise?) after shutting down car. I shut down and it makes the noise as I'm getting out - it lasts maybe 5-10 seconds. It sounds like a pump is running and a bearing is going bad. Anyone have similar experience? Attached, zipped video is about 1.5MB, 10sec long.
There is about a 3 Quart 'thermos bottle' in the drivers side front bumper. When you turn off a warm Gen2, it fills that bottle so it stays warm, and reduces the warm up time next time you drive the car.
Your Prius has an electric water pump. When you shut down the car, the pump moves coolant from the engine into an insulated tank to keep it warm. When you start the car, the pump moves the warm coolant back in. This helps three ways: the engine warms up faster, thus producing a little less pollution; the heater starts working sooner; and the engine doesn't have to run as long when you need cabin heat, thus improving fuel economy. The noise you hear after shutting down is the electric water pump.
Normal as mentioned by others. The bearing going bad noise is probably some air in the system. Mine will make the exact sound sporadically. when the air pocket isn't at the pump it sounds normal and near silent. I don't recall where, but someone tested their pump throughout the fluid draining process and when it got air that's the same sound it made. If its doing it every time, maybe there's too much air in there (from what I've read it's hard to purge all the air out)
From posts above, the noise is an electric water pump. And the ugliness of the noise could either be air in the coolant system or a bearing going out. I haven't found a thread on replacing a Gen 2 electric water pump or purging air from the coolant system. Does anyone know either procedure?
FWIW, there are several electric pumps on the Prius that work with the coolant system. Concerning purging air in the ICE coolant system, this would be a good place to start. 07 prius check engine light. need to bleed the air in the coolant? | PriusChat For the record, the sound of the CHRS pump will vary due to several things. One of those is voltage coming the auxiliary 12 volt battery. That pump will get noisier than normal if the 12 volt is weak. There are several other causes for the sound change, but low voltage will make the sound louder than normal. Also the search engine here on PC is very weak. Use Google and you will not have problems finding the information you are searching for.
