Hi all, I’m experiencing a cabin heating issue on my 2011 Prius Gen 3 (UK RHD, London). Here’s a summary: Symptom: Cold air from most vents Mildly warm air from left vent only Fan works fine Engine heats normally What I’ve checked / considered: Coolant level normal, no leaks Left vent has mild hot air, so heater core is likely okay One garage suggested regassing A/C (most probably irrelevant) Another suggested heater matrix replacement (£450+, 4–5 hr job) — maybe unnecessary What I suspect (also based in online searches): Air-mix / temperature blend actuator failure (air-mix servo) Part info: OEM part numbers suggested online: 87106‑47030 (latest), 87106‑47020 (older compatible) Questions: Can anyone confirm this is almost certainly the air-mix actuator? Anyone had this type of issue? Approximate cost if done independently? Thanks in advance for any guidance!
So your hose is on the firewall going to your heater core one goes in one comes out they're hot as fire all the time forever except at start in am etc . You know this . Then it's that lil motor actuator . Crack it open you'll see all the nonsense.
The A/C will NOT effect the HEAT! You should stay away from that guy! It's likely a vent that the arm has broken, or the servo.
In a gen 3, I think I could confirm it's almost certainly not that. I think some trims of gen 4 maybe allowed driver and passenger to set different temperatures, and had two air-mix doors, but gen 3 has just one air-mix door for both sides, which couldn't easily cause the symptoms you've described. It might rather be that some of the passages of the heater core are clogged.
In this sites logs . They're thousands of posts involving overheat and color diagrams that folks put red lines on to help folks follow along . I Google hosing diagrams are available as fast as ya can lift finger after typing . And you folks on AI bandwagons shouldn't ever really need dialogue again he he he. Ut it's all here maybe 20 yrs worth by now. Looking at list of members reveals very quickly who is who and posting pics and diagrams .
I've had this exact issue in the UK on a 2010 Prius. I've replaced the water pump and thermostat and still no luck. I think there may be air in the coolant system as every so often I can hear a swishing sound behind the glovebox (UK LHS). I also get a flashing temperature light when doing 60+ on a motorway uphill. I've tried to bleed out several times but had no luck. One thing I did try was when heating up the car after a coolant change, turning the AC on would kick the fans to start otherwise they would never run in maintenance mode. Interested to see how you get on.
If you fill it SLOWLY, a cup or 2 at a time, it will allow the coolant to push the air out. People fill quickly, which causes air to get trapped. Top off to the "B" mark. Start the car and let the engine kick in, keep an eye on the coolant level, it will drop some. After the engine stops, the level will likely be around the "full" mark. Add coolant as needed. Drive the car for 5 minutes or so and try to keep the engine running. Turn the heat to the hottest setting. It should start getting hot quickly. Park the car and let it sit for an hour or so and check the level. Add coolant if needed. Let it sit overnight, then check the coolant level. I've been doing it this way since the mid 80's and never had an issue with air in the system, any system. Toyota has a vacuum system that sucks the air out then pushed the coolant in.
