Radiator bleeder valve stripped, what should I do?

Did you try with a proper size allen wrench? I know your smaller one isn't working.

Mechanics probably don't even use that bleeder valve, they use a vacuum device when putting coolant in the car, no bleeding necessary.

To answer your question, you should try to tighten the bleeder valve and then put coolant in the car.

1. Run it with the heat on high until the car gets hot air blowing and keep adding coolant until it's full and the level doesn't go down anymore. Put on the radiator cap and let it run for a minute. Turn off the car and wait til it cools.

2. When the car is completely cool (will be a few hours), open the radiator cap and fill the coolant again until it's full. Repeat a few more mornings and you should be good.

 

Is it loose or tight now? I'm guessing tight?

Is it possible to get vice-grips or some sort of pliers on it, to break it loose?

There should be replacement readily available: check with dealership parts department.

 

If the bleed valve is open it would turn easily.

 

whatever you do, don't drive without coolant in this car

 

If bleeder is still closed you should be able to bleed the system without using it. Bleeder is in the driver side of the radiator so what you need to do is to lift the passanger (front) side up when filling the coolant to stop air from collecting there. Because the system is hard to bleed anyways you may need to go back and forth with tilting the car. With many hard to bleed cars I have just driven up to a hill while bleeding. Look for the bleeding instructions to find how to bleed the heat storage system.

 

Here's a pic of the radiator bleed plug:



13 in/lb torque is more-or-less one ft/lb.

^ Try this first. Maybe try to grip it with serrated jaw pliers at the same time, turn the two in tandem. If possible.

More info in the attached.

 

I think a replacement would be one of these two part numbers, found on this page:

16417-20290
16417-21280


RADIATOR & WATER OUTLET. 2008 Toyota Prius Hatchback HYBRID | Toyota


Strangely though, both of those parts look like the drain plug. Maybe just check with a dealership parts department, confirm the part number. Is it metal or plastic btw?

 

I had to replace my Prius 2nd Gen Bleeder Valve because it was completed corroded and the 6mm hex key wouldn't turn it. I hammered a flat screwdriver into the old plastic bleeder valve and turned it counterclockwise to take it off. Here's a photo of the new parts (bleeder valve and O Ring), part numbers, and location of the bleeder valve.