I think my thermos pump quit... the one that fires up when you shut off the car. I don't see any trouble lights and don't think there are any trouble codes on the Scangauge, its just that the motor that starts a couple seconds after shutting off the car is not going on anymore, at least for the last 2 shutdowns. It has wailed periodically over the winter, maybe now it's out of its misery? How common is it for this pump to fail after only a year?
The pump makes more noise in the winter. Also, the pump operation is keyed to coolant temperature, so it doesn't always run. That said, they do fail, so if you are not sure, get it checked. Tom
It failed to run twice yesterday... this morning, after a trip of the same duration and temperature, it DID run upon shutting down, and it didn't sound abnormal. I have never noticed it not running upon shutdown before. Even after a year, this car comes up with new things to learn! So I guess there's nothing wrong. I would imagine if it ever did totally fail, the only indication would be a decrease in mpg the first 10 minutes. It runs after the car is turned off, probably the computer is turned off, so it would not throw a code if it failed, right?
I don't know about the code, but you are correct that there wouldn't be any danger to the car, just a potential mileage hit. Tom
if engine coolant is boiling it will wait for it to settle before dropping it into the thermos so when you turn off the car, and you didn't hear a sound, you drove for a long time and you didn't use the heater plus it was a hot day if you turn on the car, and no sound goes about then the coolant is still warm and its already in the engine, users with Engine Block Heaters will definately notice this effect. If the sound does come on when you plugged your car in then your EBH is not working, although you should realize that when you unplug your car there should be sparks from the extension cord.
The prius thermos also runs in an "heat storage" mode, especially if your coolant temp goes above a certain threshold, at which time it will swap out the hot coolant in the engine with the cooler coolant in the thermos. After awhile, the coolant in the thermos may be just as hot as the coolant in the hot engine, and thus it may decide to forgo pumping the hot coolant in the engine into the already-hot thermos. (assumption made based on ken's posting of the specs of the thermos)
Every time I read info like this, I become more amazed at what an incredible engineering feat the Prius is. Makes the Space Shuttle look like a model-t. I wonder what Toyota will come up with 10 years from now?
I can only hope it is almost as good as what Toyota came up with ten years AGO. I'm driving one of their cars that doesn't HAVE engine coolant. Nor oil. Nor spark plugs, air filters, exhaust or gasoline. And while I'm on my mini-rant... if the Prius is so gosh-darned advanced - why does it still have incandescent interior lighting? Why does it even allow the Aux battery to over-discharge. And when that DOES happen, why doesn't it allow us to jump it from the traction battery? And on, and on, and on.... Sorry... OT. Back ON topic... I don't hear my pump running consistently either. Never has. It *seems* consistent, but then it'll miss ever now and again. As others have pointed out, I don't think it is ANYTHING to worry about.
