Endless Coolant bubbles when bleeding and Small amount of oil coming from headers

[XtraSilent]

So recently I bought a Gs300, I’ve been doing a little work to it this past few weeks. I changed the radiator, thermostat, water neck o-rings due to small coolant leak, radiator hoses, valve gasket, now I flushed it with 3 gallons of distilled water and am in the process of adding coolant. However, during this process, I’ve come upon a endless stream of bubbles, big, tiny, but it didn’t originally do it the first few flushes, the water was originally completely stationary, now after 3 or so drains, it won’t stop bubbling. I’d also like to know how much coolant is in the block, as well as if I need the fans to turn on in order to get all the old coolant out, bc they never came on last night doing the flush(car never overheated, but I plan to change the sensor bc it’s surprisingly cheap for the OEM sensor on eBay) , so I drained the radiator and called it a night. I haven’t touched it any today, I’ll take a look tomorrow, is it just the water boiling? Secondly, I have a tiny bit of oil coming out of the top of the Headers, I found a forum saying it was oil that seeped through from the leaky valve gasket, can anyone confirm? Forms a small bubble at the top, and a little pool of oil. You might assume head gasket automatically, but prior to all of this, I drove it 2hrs with a leaky valve gasket(smoke coming from headers, dangerous I know). Thanks in advance! I’m new to the forums (attached coolant video)

[RX400h]

This may help:

What Does It Mean if Car Coolant is Bubbling? | Prestone (holtsauto.com)