I test drove a 2006 Prius today and after the car was shut off there was a hydrolic high-pitched sound (which is normal) but after that there was a flushing sounds, like water going down a drain, but with a bit a sizzling noise...Is that normal? A friend of mine who owns a Prius said he has never heard that sound. Thanks
Normal...that's a feature where the warm coolant is pumped into a thermos where it's kept hot until the next time you start the car (up to about 48 hours)...this helps reduce start up emissions and speeds time to full warm up. Cool huh!
I've had my car for three weeks and DID NOT know this. NEAT! Yet another reason to love my little car! Billarb
I think your talking about the hissing sound of the gas tank leakage detection system (not sure what the official term is)
Actually, it's more like a gurgle than a hissing sound. Efusco's explanation sounds correct. Is there any Prius documentation I can read about that? I did a search and couldn't find anything.
There is a powerpoint presentation that explains this very well: Search google under "johns stuff toyota prius tech presentation" it should be slide 41.
There are also two facing pages in the owners manual dealing with the "unusual sounds" the Prius makes. It basically says "anything you hear is normal, be happy". They include: 1. Coolant transfer pump at startup and shutdown. It should "purr or whir", not squeal. If it squeals the pump bearings are failing, and the pump needs to be replaced. 2. A very high pitched squeal (most will not hear it it's so high) - it's the inverter. 3. Sometimes the fuel vapour recovery system has to depressurize when you shut down, and sometimes the valves will make whistling or squealing noises. Some even moan. This sound comes from the area of the filler cap/fuel tank. 4. The brake system has an electric hydraulic pump, which will run in short bursts to maintain pressure. You will hear this if you press on the brake pedal, even if the car is off. 5. Hours after you shut down the car will test certain systems, and you will hear clicks and whirs when this happens (sorry, I don't remember which systems, because I'm old, and while I have a good memory, it has a short latency period ).
