Just picked up a '08 Prius. Nice car. The coolant valve was just recently replaced. However I am getting CEL with P1116, P1121. Which indicate low coolant or at least air in the system. And the position sensor (for cooling valve?). It was making bizarre sounds in the engine compartment and the heater core. I followed Wang's procedure and the noises are now gone. It sounds just like the old one. But a quick drive today threw the CEL again. My concern is I haven't been able to get the air bleed on the radiator to open. I think(?) it's plastic but it has refused to budge. I hesitate to use a *longer* wrench. Without a replacement anyway. Suggestions, replacement bleed item info and whatever else you can suggest I have yet to do. My minivan mpg is causing me heart problems. I need to get back to 40+mpg.
That little plastic allen headed bleed screw can be a struggle to remove. I suggest ordering a replacement screw and having it in standby in the event you destroy the one that is in there. Toyota p/ns for the bleed plug and oring should be 16417-20290 and 16492-21050. But confirm for your application. Beyond a spare bleed screw, the Lisle No-spill funnel that Patrick recommends is good to have and if money and equipment allow an Airlift is a handy tool to bleed these cooling systems. YouTube Lucious Garage, Caroline uses one in a couple Gen 2 videos there for inspiration.
