2008 Prius Not Heating - Air Coming from Upper Vents

You should check the radiator fluid to make sure it's full. You would need to remove the radiator cap to see if it's full, don't rely looking at the reservoir level.

If it's not full, fill it with Toyota pink super long life coolant and make sure you bleed all the air out. Many times if there's a leakage and air enters the system, you will lose your car's heating.

 

You also could check the heater hoses under the hood for warmth. If the coolant level at the radiator is OK and there's no heat, there's an electric pump in the heater core loop that can be checked. Is there a check engine light? A P1121 code for the coolant control valve could cause no cabin heat.

My Prius is not here so I can't check, but I believe the dash vent heater control only closes the two center vents. The two outer vents by the doors may only have manual control, to help keep door windows defrosted. My other car is like that, at least, and that could explain why there's cold air in the face.

The Prius has electric cabin heater elements that are pretty minimal, and would explain why it takes a long time to get warm if they're the only source of heat. They would probably not heat dashboard air at all.

 

Check the coolant level in the radiator. Don’t just check the overflow bottle. You do need to (at least) partially remove the plastic cover above radiator cap. Only open the cap with cold engine! If you did need to fill it drive it and recheck it to make sure all the air is out. And only use the correct Toyota SLLC-coolant. Also check the overflow (its right next to the cap). If it was low check water pump (belt driven pump on engine) for leeks.

Even when mode is set to floor some air is flowing thought other vents to keep the windows from fogging. Just check the vent actuators by putting fan on high and testing all blower modes if you are concerned about this.

Are there any fault lights on? If not then coolant control valve works (non-working valve would cause fault code and light). If there is heat when engine is running but not when it could be the (electric) heater coolant pump.

 

I know a coolant heat storage pump/valve problem would give a code, but how about the A/C water pump (W1 in my wiring diagram)?

To the OP, bleeding air out of the engine coolant loop in this car is a little involved. You need to manually operate the above-mentioned coolant heat storage pump, and use tubing connected to the radiator bleeder valve. There are other threads about that.

 

i thought the gen II had a manual pump and belt?

 

Sorry I mixed it up I meant the coolant control valve. I will fix the original post.

If level has only dropped down less than liter/quart it enough just to fill the radiator. Drive, let it cool and fill it again. How many times you have to do this depends on how much you needed to ad.

Yes belt driven pump pumps the coolant around when engine is running but electric pump pumps the coolant to heater core when engine isn’t running.

 

thank you.

 

Is your heating problem fixed. I have a prius v 2012 and i have them same issue.

 

You've given me a serious case of déjà vu lol. (See post #2)