Sorry again for no updates in a while. A lot has been going on with the build. About a month ago I pretty much finished up everything and got the truck back together. I started to go through my fluid fills (coolant, oil, transmission, gearbox). A bought a knock-off vacuum fill kit, which is identical to the Astro Pneumatic 78585 kit, but for less than half the price. Since I've heard horror stories about air lock and overheating in these LS engines, I thought I would give this a try. The kit draws vacuum on the cooling system and pulls all the air out of it. It then draws the coolant from a holding bucket into the system, eliminating any air pockets.
Here is the vacuum kit hooked up to the coolant system.
You use shop air to create a venturi effect to draw vacuum on the system.
I drew the vacuum down to about 23 inches of mercury.
It flattened my upper radiator hose except where I had the stainless steel tubing inside.
The lower hose was flat as a pancake.
