which noise is which?

<div class='quotetop'>QUOTE(cwerdna @ Jul 3 2006, 11:00 PM) [snapback]280865[/snapback]</div>

all great questions...I will try to help, but others with more technical knowledge can probably answer with more detail:

-First you hear the coolant noise
-Second you hear the brake pressure noise
-I am not sure about the repeated pumping noise, unless you are hearing the coolant being pumped back into the engine right after you hit the start button.
-Brake buzzing noise, I believe this has something to do with regeneration / use of the electric brakes (others can elaborate more)
- Yes, the Japanlish is trying to say that the coolant noise will happen each time you shut down no matter how long your drive
- Yes, I have heard the electric motor noise (fuel evap leakage check), and it pretty much sounds like a little buzzing electric motor (although mine is only on for a few seconds)

 

<div class='quotetop'>QUOTE(cwerdna @ Jul 4 2006, 02:00 AM) [snapback]280865[/snapback]</div>

Yup. Sounds like the coolant being pumped into the thermos to me.

<div class='quotetop'>QUOTE(cwerdna @ Jul 4 2006, 02:00 AM) [snapback]280865[/snapback]</div>

I don't know what that is, but, as mssmith95 suggested, it would be logically consistent with that being the coolant being pumped back into the engine.

<div class='quotetop'>QUOTE(cwerdna @ Jul 4 2006, 02:00 AM) [snapback]280865[/snapback]</div>

This is definately the brake accumulator pump. This actually really freaked me out when I first got the car and I thought I was going to have to take it back for service. I read a good description on this board at one point that I'll now try to recreate, but may screw it up slightly. Basically, on a normal car, brake pressure is kept up by the (gas) engine. The "challenge" with the Prius is that the gas engine isn't always running (and you usually want to have brakes, even when you're in EV mode ). So, that means that you have to use an electric pump to keep up the pressure in the brake lines up.

You can easily recreate the sound by pumping the brakes while the car is in Park. Just pump the pedal 3 or 4 times and you should hear the brake accumulator pump.

 

We need a Prian - English dictionary, LOL

 

I'd like to elaborate on the fan/pump noise that cwerdna was hearing. Mine happens every time the fan comes on and it sounds like it's running fine then it sounds like it's sick and then back again repeatedly until it shuts off.

I just took it in to the dealership thinking that maybe it was going out but after looking at it they said it's normal (though I only remember hearing it this "new" way for the past couple of weeks). I know that you might think that maybe I'm just not very observant but this is the first car since my very first car ever that the fan keeps running even after the car has been turned off. This being the case, plus the fact that it's on the driver side and I walk past it every time I get out of the car, yes I notice it every time.

They also said that many of their customers have been complaining about it and that maybe there will be a recall on it but I wanted to get other owners' feedback on it.

I hope I've explained myself enough, if not, please let me know and I'll try to elaborate more : )

 

As I've posted before, there are two facing pages in the owners manual about the sounds Prius makes. The gist of all that is "the odd noises that you hear are normal".

When you turn the car on or off, you will hear a faint clicking of the valves setting and then the whir of the coolant transfer pump, putting warm coolant into the thermos or taking it out. If it squeals the bearings are going and it needs to be replaced (warranty).

When you start the car you will hear a very brief pump sound, and you will hear it about 1 in 3 times you step on the brake pedal. It's the brake fluid pressure accumulator pump for power brakes. Prius needs this as it can't rely on engine vacuum for power brakes, as the engine doesn't run all the time like it does in guzzlers.

After you have shut the car off and it has been sitting for awhile (more than a few minutes) you will hear the odd click. This is various relays opening and closing, particularly if you have the FOB in your pocket. The car senses you are near and -may- want to operate the car. It "gets ready". This is also in the owners manual.

I've so far never heard the five hour fuel pressurization test so I can't describe it for you.

 

Okay so that's what I would like clarification on. The dealership said that the sound I am hearing is the "purge valve" and proceeded to try to make me feel like an idiot by stating that this is a "totally different technological vehicle". No s**t but the sound of the pump isn't supposed to change from high to low like a kid entering adolescence is it? Personally I don't think so, but then again I don't work for Toyota.

As far as all the other noises, they make sense. I understand them and they don't bother me. I just know after walking in front of my own car for a year that when the fan is on, transfer pump, purge valve or whatever else it is that still remains running after the car has been shut off, it didn't (before) make the sound it's making now; which is the "sick" sound it makes until it eventually shuts off ("sick" of course being the sound of the pump, or fan, or whatever it is changing its pitch)

So David, if what you're saying is true, that likely it's a bearings issue and should be replaced what can I, as already having been told by my Toyota dealership that it's "normal noise", do?

 

You can try showing them this TSB. Humming is okay, but it's not supposed to sound squeaky.