Please help….what is this part number?

I'd back mine out if it'd help, but suspect there'd be coolant leakage, and I don't want to go there. I'd suspect there's an O-ring of some sort on it, and you won't find anything suitable.

If you need the car functional ASAP, I'd either:

1. Buy a complete new joint (likely with no bleed screw).
2. Take the current one off, clean it, and fill the voids left by the missing bleed screw, and the spigot where the coolant would come out, with two-part epoxy.

I'd be leary of #2, just in case it didn't hold.

 

If you've got the revised part, the one that comes with no bleed screw, it's not going to leak. You can verify: just plug all holes but one, and try to blow air through.

 

Simplest thing to do is just replace the old part with the new part. There will end up not being a white air valve, just like there hasn't been in any Prius since Toyota figured out they didn't need it. Done.

Apparently because the system is already a degas-bottle design, and when you follow the normal fill instructions, warm up the engine, shake the hoses, the air you didn't let out of the silly valve gets carried back to the degas bottle anyway, just like it's s'posed to, and you're done.

Elektroingenieur checked the later edition repair manuals up in post #10, and sure enough, they just stopped mentioning the silly air valve, and they did not add any other step for you to fuss with in its place.

 

It is not that straight forward. Yes, the air gets vented through the degas bottle. Here is the problem: The capping machine puts a vacuum on the system. This vacuum can pull in lots of air through the vent. So, it is not that straight forward to cap the system. You may need to first use a venturi vacuum pump to suck the air from the system.

 

what?

what?

what?

and what?

The cooling system can be routinely drained and refilled, at atmospheric pressure, following only the instructions in the repair manual.

In early Gen 3, there was that valve there, and the instructions included using it.

In later Gen 3, the only change to the system was to delete that valve, and the only change to the instructions was to delete fussing with that valve.

And even for an early Gen 3, if you buy a new part to replace that union, it will be the version with the valve deleted.