engine water pump failed to seal?

You just keep filling the radiator an ounce at a time top of neck it gurgles down add another 45 min later water will stand at top of neck 5 full minutes without moving a bit . When it does that cap the radiator make sure the jug is full and you ready to ride . Heat on full tilt. You should have heat within 3 minutes and turning down of warm. Out . 10 min later back on park lot . Touch hoses top and bottom should be near same temps etc just still at same level as 10 min ago .

 

Just thought I'd check that. FWIW, one of the bolts is 11 lb-ft.

 

For the OP. Go on youtube and look up "eyeonaiman". The kid has two very nice videos about filling and burping the coolant system. Here is one of them:

 

A vacuum fill system is relatively easy and reliable.

 

Use a Lisle "no spill" funnel or a knockoff of it. Harbor Freight sells one, that is what I used. It clamps onto the radiator filler neck so that no fluid can go out the side. Since filler necks come in various sizes these funnels come with an assortment of "caps" and one will fit (unless maybe you have a very rare vehicle). Be careful attaching it on a Prius, the filler neck is kind of fragile - you want to support it while attaching the funnel.

Here is the Harbor Freight part:

https://www.harborfreight.com/no-spill-radiator-funnel-kit-58423.html

and here is the Lisle part, which oddly costs less than the HF one today:

(Amazon links don't work, go there and enter: B00A6AS6LY)

Hmm, I see that some of the knockoffs now use a petcock (valve) below the funnel. That would be more convenient than the "plug on a stick" of the original design. Although it might be hard to get all the coolant cleaned out of it, which could result in a little mixing if the same funnel is used on different types of cars. Not recommending it, but for instance, see this Amazon listing: B09XT1XC55.

 

It is possible to fill a cooling system with a funnel that does not seal at the inlet. Patience.

Many "content creators" assume techniques used for 75 years with tools readily available at the auto supply are obvious. Regardless content creators are typically not trained in content or in instruction. Kind of the Ai paradigm once again.

Having proper lighting is a plus.

Avoiding the trap of confirmation bias is a hard learned lesson for some.

You should look into vacuum filling - a technique not as well known by shade tree mechanics but easy, affordable and the method real shops use on complex cooling systems like gen2.

 

FWIW, repair manual instruction attached. Pretty sure it involves Techstream.