I'm finally getting to the fun parts! After installing the oil catch cans, the last thing to do before first start was to fill fluids (oil, trans, and coolant) and check for error codes. Of course there's also all the other check to make sure things are all done, like torque lug nuts, suspension bolts, make sure things are greased, etc., but those were all double/triple checks for me at this point.

Upon the advice of Kiwi Dave, I purchased a vacuum radiator fill tool that uses a venturi and shop air. I used it and thought I was going crazy - I couldn't get more than about -5" mercury, which wouldn't hold for any amount of time. I had already capped the extra line that ran to the secondary OEM tank, and verified that that was not the leak (and indeed pulled vacuum. I knew I had a leak somewhere, but no way to find it. I figured the quickest/cheapest way to find it was to just start filling the system with distilled water: at $89 a gallon I didn't mind losing some, and I was going to have to add some anyway to dilute the full-strength coolant I bought anyway. I started filling ... quarter gallon ... half gallon ... nothing. Three-quarters. Look down, and finally a wet floor! I trace the leak luckily to a place I could access, right behind the passenger exhaust up-pipe to the turbo.

PXL_20210113_000849012.jpg

I thought it was leaking some from both the banjo and the lower fitting. After removing the exhaust pipe (with a nut/bolt that refused to separate except with some extreme measures), I found that the lower fitting was oil and the upper one was a banjo that I guess I ad just never torqued when reinstalling the heads. Lesson learned, and better now than later!

PXL_20210114_002058162.jpg

After torqueing the banjo, I was able to pull vacuum and fill the radiator system pretty quickly. It's a wonderful tool. Then I also topped off the spare tank to make sure there was sufficient reserve to pull extra if necessary after the engine was turned over a few times. I used about 1 1/2 gallons of water, 1 1/2 gallons of coolant, and two little bottles of the OEM coolant additive.