I just got an '05 Prius with 70k miles and I'm still trying to figure it out. First of all, sometimes after I drive it for a while and I turn it off I hear a humming/spinning sound for 5-10 seconds or so and then it stops. Is this normal? Also, sometimes it take a few minutes for the A/C to start blowing. When i turn the heat on, nothing will come out at all within the first 5 minutes or so, then hot air will start blowing. Is this normal? Thanks. Chris
The Gen II Prius has a thermos for hot antifreeze, it pumps it there when you stop to help warm up a cold engine when you restart. The Prius does seem to know when you want hot air and it only has cool air, it will not blow cold air but will wait til it has warm air.
You have a happy Prius. It's simply humming a little happy tune of satisfaction after another successful journey. As stated in the previous post, it's the coolant transfer pump. Tom
If it is a humming sound, it may be normal. If the hum turns into a "whine", a "moan," it may mean the Coolant Heat Storage Water Pump, just behind the front left headlight, is having problems. This is under warranty for 6 year, 60,000 miles, and I just got mine replaced because of this problem. Looks like you are beyond that, though, and they say the loud whine does not interfere with the pump's work. Good luck at it.
Does this give the error code 1151? We looked at the code and it says that the 04 upon receiving this code needs a computer flash or an update. At the dealership, it costs $160!!! is there something I can do other than flashing?
Let's see if I can give the non-technical long answers: Humming: Yes, there's a thermos in which the Prius pumps the heated engine coolant. It does this so that the next time you start your Prius, all that warm coolant will flow through the engine and help heat it up faster. The thermos can maintain the coolant temp for up to three days. A/C: The air conditioning of the Prius is extremely sophisticated. On most other cars, when you turn on the A/C full-blast, the fan goes to full and the A/C kicks in. The problem is that it takes a while to cool the air. This means that the fan is blowing a lot of very hot air. Likewise, when you turn on the heat, most cars blow extremely cold air while it tries to heat it. The Prius will wait until the air is adequately cooled or heated until it blows it at you. Also, when in the [Auto] state, the Prius will not blow full-force out the dash vents; that's just rude. It will instead blow the air through the windshield vents until a lower airflow is needed at which time it will switch to the dash vents.
